Remotely controllable wireless energy control unit

ABSTRACT

A power management system and associated method includes provision of local wireless energy control units at remote sites for controlling power delivery to customer loads, and a central station with a wireless transmitter for broadcasting commands to the wireless energy control units. The wireless energy control units each comprise a bank of switches for controlling power delivery to electrical loads at each local site. The controllable switches preferably have a deformable bimetal member controlled by a heated coil for engaging and disengaging electrical contacts. Each wireless energy control unit is capable of being pre-configured so as to specify the order or priority in which electrical loads are disengaged, in response to commands to reduce power consumption received from the central station. The central station issues power reduction commands according to different priority levels or alert stages, causing the local wireless energy units to disengage local loads accordingly.

RELATED APPLICATION INFORMATION

This application is a divisional of U.S. patent application Ser. No.11/221,206, filed Sep. 6, 2005, which is a continuation of U.S. patentapplication Ser. No. 11/012,879 filed on Dec. 14, 2004, now U.S. Pat.No. 7,324,876, which is a continuation-in-part of two otherapplications: (1) U.S. patent application Ser. No. 10/007,501 filed onNov. 30, 2001, now U.S. Pat. No. 6,832,135, which is in turn acontinuation-in-part of U.S. patent application Ser. No. 09/903,403filed on Jul. 10, 2001, now U.S. Pat. No. 6,636,141, and (2) U.S. patentapplication Ser. No. 10/900,971 filed on Jul. 28, 2004, now U.S. Pat.No. 7,265,652, which is a continuation-in-part of U.S. patentapplication Ser. No. 10/307,222, now U.S. Pat. No. 6,825,750, which isalso a continuation-in-part of U.S. patent application Ser. No.09/903,403 identified above; all of which are hereby incorporated byreference as if set forth fully herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention generally pertains to systems and methods forcontrolling energy distribution at local sites.

2. Background

Electrical utilities face particular challenges in meeting continuouslychanging customer load demands. At least two related reasons exist forthese challenges. First, power demands can fluctuate substantially fromday to day or hour to hour, making it difficult for utilities to ensurethat they have enough capacity to meet demand. These fluctuations inenergy demand may arise from ordinary cyclic energy usage patterns (forexample peaking in the afternoon), or else can result from an unexpectedchange in the balance between energy supply and demand, such as where,for example, a power generator linked to the power grid unexpectedlygoes down, large energy users go on or off line, or a fault occurssomewhere in the distribution system.

A second factor contributing to the challenges faced by power utilitiesis the fact that power consumption in local areas tends to grow overtime, gradually placing increasing burdens on electrical utilities tomeet the growing demand. Because the construction of new power plants isvery costly and must comply with a variety of governmental regulations,it is possible for a local or even large geographic region to finditself without the power capacity to supply its current or anticipatedfuture demand.

A major challenge for utility companies is handling peak energy demands.This is because the energy supplied by power utilities must besufficient to meet the energy demand moment by moment, and peak demandsplace the greatest strain on the power distribution system. When energydemand outstrips available supply, disruptive events such as powerblackouts, brownouts or interruptions can occur. Not only can suchevents cause substantial inconvenience to large numbers of people andbusinesses, but they can also be dangerous or life-threatening—where,for example, the power supply for hospitals or critical home caremedical equipment is compromised.

Historically, when power utilities serving a locality have been facedwith a severe energy situation caused by high demand, their options havebeen extremely limited. Power utilities can, for example, request thatconsumers conserve energy, but not all consumers follow such requestsand, in any event, conservation has not tended to provide a completesolution for energy supply problems. Power utilities can attempt tosatisfy peak demands by purchasing available energy from a third partysource connected to the power grid, but such purchases, particularly atpeak demand times, can be extremely costly as energy suppliers oftendemand a premium when demand is high. Another option is for powerutilities to build additional power plants, but building power plantstakes substantial time and investment, and may require approvals fromstate and/or federal government authorities as well as consumerassociations.

To help reduce peak power demand and thus ward off costs associated withnew power plants or premium energy purchases, various attempts have beenmade to develop load management systems which control peak demand on thepower generating equipment by temporarily turning off certain customerloads when deemed necessary to avoid a blackout or similar powerinterruption. Generally, the types of customer loads that are regulatedin this manner involve non-critical electrical equipment such as airconditions, electric heaters, and the like.

One type of load management system, for example, uses ripple toneinjection to send coded pulses over the utility's power lines. The codedpulses may be applied to the utility power lines by way of anelectromechanical ripple control transmitter, which may consist of amotor/alternator operating through thyristor static switches, or by wayof a step-up transformer selectively connected to the utility powerlines through a passband circuit tuned to the frequency of the codedpulse signal. At the customer sites, receivers interpret the codedpulses and perform desired command functions—e.g., turning off thecustomer load(s).

An example of a particular system for load management is described inU.S. Pat. No. 4,264,960. As set forth in that patent, a plurality ofsubstation injection units, under control of a master control station,transmit pulse coded signals on the utility power lines. Remote receiverunits positioned at customer loads control the on and off states of theloads in response to the signals received over the utility power linesfrom the substation injection units, by activating latchable single-polecontacts. Different types of loads are organized into load controlgroups (e.g., electrical hot water heaters, air conditioner compressors,street lights, etc.). The master control station independently controlsthe various different types of loads through different pulse controlsignals. Each remote receiver unit is pre-coded so that it responds toone and only one pulse code signal. In order to control different typesof loads (e.g., hot water heater and air conditioning compressor) at thesame location, separately encoded remote receiver units at the locationare required. The master control station turns load groups on and off inorder to implement a load management strategy, as determined by a systemoperator.

A variety of drawbacks or limitations exist with conventional techniquesfor load management in large-scale power distribution systems. A majordrawback is that shut-off commands from the power utility to the remotecustomer sites are generally propagated over the same lines that carryhigh-voltage electricity. Because transformers are used to relayelectrical signals across power lines, it can be difficult to pass data(e.g., shut-off commands or other control signals) over power lines.Moreover, noise or interference can prevent proper reception of shut-offcommands or other control signals. Any inductance at the customer loadcan generate large harmonics, which can easily match the control signalfrequency, thus blocking out control signals or possibly causing “falsealarms.” A simple household device such as an electric oven can disruptthe reception of control signals over power lines. Over a large area,since all loads inject noise into the power distribution system, thecumulative interference or noise effect can be substantial. Thus, usingpower lines to distribute control signals can be quite problematic,because of the many sources of noise and interference. Sophisticateddigital signal processing techniques might be used to filter out thenoise or interference and reconstruct control signals, but suchtechniques are complicated and would generally require that a receiverbe quite costly.

Another drawback with conventional techniques for load management is thelack of control either at the utility or consumer level. In situationswhere the utility is forced to shut off power to one or more regions(e.g., by causing a rolling blackout) in order to prevent peak demandfrom causing a catastrophic blackout or damaging power generation ordistribution equipment, power customers typically have little or nocontrol over which loads get shed. Rather, a complete shut-down of thecustomer's power usually occurs for those customers within a regionsubject to a rolling blackout. Even in those situations where theutility has pre-configured the customer's wiring so that certainisolated loads (usually an air conditioner or electric water heater) canbe dynamically shed at peak power times, neither the utility nor thecustomer can easily alter which loads get shed unless the customer'swiring is re-configured. Where the customer loads are collectivelygrouped into different load control groups, the utility may be able toshed certain types of loads (e.g., all air conditioners) en masse, butthe choice is generally made by the utility based upon its overall powerdemands and management strategy, with little or no control beingavailable to the customer (other than perhaps initially givingpermission to the utility to shut down a specific load, such as an airconditioning unit, before the utility pre-configures the wiring tocontrol the specific load as part of a larger group of similar loads).

Another problem that remains insufficiently addressed by conventionalload management techniques is the fact that power interruptions,brownouts or blackouts generally occur with little or no warning topower customer. In some cases, where unusually large demand can beforecasted, electrical utilities have been able to provide warnings topower customers that a blackout or power interruption is likely within acertain upcoming period of time—e.g., within the next several hourperiod, or next 24 or 48 hour period. However, power interruption orblackout warnings are typically so broad and vague in nature as to be oflimited or no value to power customers, who are left with uncertainty asto whether or not their power will go out and if so, exactly when.Moreover, since power interruption or blackout warnings are normallybroadcast by radio or television, customers who are not tuned in byradio or television to the broadcast stations can easily miss thewarnings and not realize that a power interruption or blackout isimminent.

Certain power management techniques have been proposed for controllingpower consumption at a specific local site (e.g., a factory), but suchsystems are usually isolated and operate independently of the powerutility. An example of one power management system is described, forexample, in U.S. Pat. No. 4,216,384. According to a representativetechnique described therein, the various main power lines of theinstallation or site are monitored for energy usage, and a controlcircuit selectively disconnects loads when the total energy being drawnat the installation or site exceeds a specified maximum. Whileostensibly having the effect of reducing overall power consumption atthe installation or site, a drawback of these types of power managementsystems is that they can be relatively complex and costly. For example,the power management system described in U.S. Pat. No. 4,216,384utilizes a set of transformers to independently monitor various mainpower lines, a bank of LED-triggered Triacs to selectively engagevarious customer loads, programmable control circuitry, automaticpriority realignment circuitry, and so on. Because of their relativecost and complexity, these types of local power management systems arenot very suitable for widespread use, particularly for ordinaryresidential use or other cost-sensitive applications. Moreover, theiroperation is very localized in effect, and cannot be controlled from acentral location such as the power utility itself.

In addition to the foregoing limitations and drawbacks, conventionalpower and load management strategies are limited by the availablecircuits and switches which are used in some applications to controlactual power delivery at local sites. One common type of power switch,for example, for connecting and disconnecting power sources to loads isa circuit breaker, which functions to prevent an excessive amount ofcurrent from being drawn from the power source or into the load bybreaking the electrical circuit path between the source and load whenthe current limit is reached. A typical circuit breaker has a bimetalarm through which travels a power signal from the source to the load.One end of the bimetal arm is connected to the power signal line, whilethe other end of the bimetal arm is connected to an electrical conductorfrom which the power can be distributed to the load. When too muchcurrent travels through the bimetal arm, the heat from the currentcauses the bimetal arm to deform or bend in a predictable manner, whichcauses the bimetal arm to break contact with the electrical conductor,resulting in a break between the power signal and the load. In thismanner, the source and load are both protected from currents whichexceed a certain limit.

While circuit breakers are useful for protecting against high currentlevels, they are generally passive circuit elements whose responsedepends entirely upon the amount of power being drawn by the load. Theytypically do not provide active control of a power signal line. However,some resettable circuit breakers have been proposed, which utilize, forexample, a spring-operated mechanism allowing a remote operator to openand close the contacts of the circuit breaker. An example of such acircuit breaker is disclosed in U.S. Pat. No. 3,883,781 issued to J.Cotton.

Other types of remotely controlled or operated circuit breakers aredescribed, for example, in U.S. Pat. No. 5,381,121 to Peter et al., andU.S. Pat. No. 4,625,190 to Wafer et al. These circuit breakers involverather elaborate mechanisms that, due to their complexity, would beexpensive to manufacture and potentially subject to mechanical wear orfailure.

Besides circuit breakers, other types of circuits have been utilized incontrolling power signals. However, these other types of circuits havedrawbacks as well. For example, solid state switches (e.g., transistorsor silicon-controlled rectifiers (SCRs)) can be used as switches betweena power source and load, for controlling distribution of the powersignal to the load. However, transistors and SCRs generally have limitedpower ratings and, at high current levels, can become damaged orshorted. Moreover, transistors or SCRs with high power ratings can berelatively expensive.

It would therefore be advantageous to provide a load management systemthat overcomes one or more of the foregoing problems, limitations ordisadvantages. It would further be advantageous to provide a loadmanagement system that gives more flexibility to power utilities and/orconsumers, that is not subject to the noise and interference effectscaused by transmitting data over power lines, and does not require arelatively expensive receiver. It would also be advantageous to providea load management system that uses a controllable electronic switchcapable of selectively connecting or disconnecting a power source to aload and, in particular, a switch that is reliable, durable, andlow-cost, and that can handle relatively high power demands, such as maybe required for residential or commercial applications.

SUMMARY OF THE INVENTION

The invention in one aspect is generally directed to systems and methodsfor managing or controlling power distribution at local sites.

In one aspect, a local energy control unit includes a set ofcontrollable switches for controlling power delivery from a power supplyline to individual electrical loads. The energy control unit preferablycauses the controllable switches to engage or disengage their respectiveelectrical loads, in a configurable order, when an external command isreceived. The energy control unit can be user-configured (e.g.,programmed) to prioritize the order in which loads are disengaged. In apreferred embodiment, the controllable switches are electricallyconnected in series with (e.g., downstream from) a set of circuitbreakers, and the controllable switches are preferably capable ofselectively disengaging and re-engaging electrical loads as may bepresent, for example, at commercial or residential electrical outlets,while drawing little or no power when conducting.

In another aspect, an energy management system and associated methodtherefore involve the use of remotely located energy control units atvarious customer sites for controlling energy distribution to customerloads. The energy control units each preferably comprise a set ofcontrollable switches for controlling power delivery to various localelectrical loads. A user may pre-configure the energy control unit tospecify the order or priority in which electrical loads are disengaged,in response to commands to reduce energy consumption. A wireless commandsystem allows the energy control units to receive commands from adistant location, such as a central transmitter or a collection ofgeographically dispersed transmitters. A central station can issueenergy reduction commands or other similar messages according todifferent priority levels. The energy control units respond to theenergy reduction commands by disengaging one or more electrical loads inaccordance with the priority level of the energy reduction command. Bythe collective operation of the local energy control units at theirvarious remote locations, a substantial overall power reduction can berealized, particularly, for example, at times of peak power demand.

In various embodiments, the local energy control units may be outfittedwith added features that enhance their utility. For example, in certainembodiments, an energy control unit may be configured with aprogrammable timer function, allowing the priority by which thecontrollable switches are activated to automatically adjust based uponthe particular day of the week, time of day, and so on. The energycontrol unit may also be configured with a memory to record the statesof the various controllable switches, or other system parameters, overtime. The memory may be triggered to record only after an event whichcauses one or more electrical loads to be disengaged.

In a preferred embodiment, a controllable electronic switch, as may beused in various embodiments of an energy control unit having a set ofcontrollable electronic switches for selectively disabling localelectrical loads, comprises a deformable member (e.g., a bimetal memberor arm) anchored at one end and in controllable contact with anelectrical conductor at the other end. An incoming power wire isconnected to the bimetal member near the contact point with theelectrical conductor. A heating element (such as a coil) is coupled tothe bimetal member, and is controlled by a switch control signal. Whenthe switch control signal is not asserted, the heating element isinactive, and power is delivered through the incoming power wire acrossthe end of the bimetal member to the electrical conductor, from which itcan be further distributed to the load. When the switch control signalis asserted, the heating element heats up causing the bimetal to benduntil the contact with the electrical conductor is broken. Theelectrical path from the incoming power wire to the electrical conductor(and hence, to the load) is then broken. So long as the switch controlsignal is asserted, the heating element continues to keep the bimetalbent and the electrical path broken.

Further embodiments, variations and enhancements are also disclosedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a power management system according to oneembodiment as disclosed herein.

FIG. 2 is a block diagram of a local energy control system as may beused, for example, in accordance with the power management system ofFIG. 1 or other power management systems.

FIG. 3 is a diagram illustrating physical placement of certaincomponents utilized in one embodiment of a local energy control system.

FIG. 4 is a conceptual diagram of a bimetal-based circuit breaker asknown in the art.

FIG. 5-1 is a diagram illustrating an example of the flow of electricitywhen the circuit breaker of FIG. 4 is closed (normal operation), andFIG. 5-2 is a diagram illustrating an example of how the bimetal of thecircuit breaker breaks the circuit connection when an over-currentsituation occurs.

FIG. 6 is a diagram of a controllable electronic switch as may be usedin various embodiments of power management systems as disclosed herein.

FIG. 7-1 is a diagram illustrating an example of the flow of electricitywhen the electronic switch of FIG. 6 is closed, and FIG. 7-2 is adiagram illustrating how the bimetal of the electronic switch of FIG. 6breaks the circuit connection in response to assertion of a controlsignal.

FIG. 8 is a block diagram illustrating another embodiment of acontrollable electronic switch as may be used in various embodiments ofpower management systems as disclosed herein.

FIG. 9 is a block diagram of another embodiment of a local energycontrol system as may be used, for example, in various power managementsystems as disclosed herein.

FIG. 10 is a diagram illustrating various components of a local energycontrol system in relationship to one another.

FIG. 11 is a state diagram illustrating the transition between variousalert stages, according to one process as disclosed herein.

FIGS. 12 and 13 are process flow diagrams illustrating various stepsinvolved in transitioning between different alert stages, according totwo different embodiments as disclosed herein.

FIG. 14 is a diagram of another embodiment of a controllable electronicswitch using a wedge to break electrical contacts in a circuit path.

FIG. 15 is a diagram showing an example of how the controllableelectronic switch shown in FIG. 14 breaks an electrical connection.

FIG. 16 is a diagram of another embodiment of a controllable electronicswitch using a wedge to break electrical contacts in a circuit path,having a mechanical cam with multiple latching positions.

FIGS. 17-1, 17-2 and 17-3 are diagrams illustrating the controllableelectronic switch of FIG. 16 with the latch in an engaged position withrespect to the cam.

FIGS. 18-1 through 18-8 are diagrams illustrating different latchingpositions of the cam of the controllable electronic switch of FIG. 16.

FIG. 19 is a diagram of yet another embodiment of a controllableelectronic switch using a wedge to break electrical contacts in acircuit path, having a mechanical cam with multiple latching positions.

FIG. 20 is a diagram showing an example of how the controllableelectronic switch shown in FIG. 19 breaks an electrical connection.

FIGS. 21, 22, and 23 are simplified schematic diagrams illustratingexamples of control circuits or portions thereof that may be used withvarious controllable electronic switches disclosed herein.

FIG. 24 is a diagram of one embodiment of a switch control circuit asmay be used in connection with various controllable electronic circuitembodiments shown or described herein.

FIG. 25 is a diagram of another embodiment of a switch control circuitas may be used in connection with various controllable electroniccircuit embodiments as shown or described herein.

FIG. 26 is a diagram of another embodiment of a controllable electronicswitch.

FIGS. 27-1 and 27-2 are diagrams illustrating operation of thecontrollable switch depicted in FIG. 26.

FIG. 28 is a diagram of a controllable electronic switch, utilizing apair of opposing deformable members.

FIGS. 29-1 and 29-2 are diagrams illustrating operation of thecontrollable switch depicted in FIG. 28.

FIG. 30 is a diagram of another embodiment of a controllable electronicswitch having opposing deformable members, along with an overridecontrol.

FIGS. 31-1 and 31-2 are diagrams illustrating operation of thecontrollable switch depicted in FIG. 30.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a block diagram illustrating an example of a power managementsystem 100 in which local energy control units, according to variousembodiments as disclosed herein, may be utilized. As shown in FIG. 1, apower utility 105 distributes power to a variety of customer loads 120at local sites 109, over power lines 108. The power utility 105 isillustrated generically in FIG. 1, and may encompass one or more powergeneration stations or other power sources, substations, transformers,power lines, and any other equipment which is utilized in generating anddistributing power to customers, as is well known in the art. The localsites 109 may include industrial/commercial users (which typically drawpower in the neighborhood of 4.16 kV to 34.5 kV) and residential orlight commercial users (which typically draw power in the neighborhoodof 120 and/or 240 Volts), although more generally they include any setof related electrical loads for which control of energy distribution isdesired. Each of the customer loads 120 thus generally comprises one ormore local electrical loads (not individually shown in FIG. 1).

At each local site 109, a wireless energy control unit 114 controls thedelivery of power from the power lines 108 to the customer loads 120. Acentral station 102 transmits energy control commands, via acommunication unit 103 (which preferably comprises at least atransmitter but may also include a receiver for two-way communication),to the local wireless energy control units 114 located at the variouslocal sites 109. Each of the wireless energy control units 114 maycomprise a communication unit 115 (preferably comprising at least areceiver but may also possibly a transmitter for two-way communication)and a power control circuit 112 for, among other things, interpretingthe power control commands received by the communication unit 115 andacting thereon. At each local site 109, as explained further herein, thepower control circuit 112 receives the energy control commands via thecommunication unit 115 and selectively blocks power to one or moreindividual electrical loads at the local site 109, by selectivelyengaging or disengaging various local power distribution lines 118 atthe local site 109.

The central station 102 may transmit energy control commands to thelocal sites 109 using any suitable communication protocol or technique.The communication may be either one-way or two-way. In a preferredembodiment, the communication unit 103 comprises a radio frequency (RF)transmitter, and, in such an embodiment, the central station 102preferably broadcasts energy control commands over radio frequenciesusing available sidebands (e.g., FM sidebands) and/or using frequencyshift keying (FSK) transmission. However, other wireless communicationtechniques or protocols—for example, spread spectrum or widebandcommunication techniques or protocols—may also be used. While thecentral station 102 is illustrated as a single feature in FIG. 1, itwill be understood that the transmissions from the central station 102may be relayed over a variety of communication equipment and facilities,including communication substations and landlines.

An advantage of wireless transmission of energy control commands is thata relatively wide area can be covered relatively economically, withoutthe need, for example, for continuous wired landlines from the centralstation 102 to the various local sites 109, or the need for transmittingdata over noisy power lines which are generally subject to local andother sources of interference.

In a preferred embodiment, each wireless energy control unit 114provides the customer with the ability to pre-select which electricalloads, if any, at a particular local site 109 should be disengaged inresponse to command messages from the central station 102. This abilitymay be described in more detail with reference to FIG. 2, which is ablock diagram of a local energy control system 200, as may be utilizedin connection with the power management system 100 shown in FIG. 1 (andmay be loosely correlated to the various components shown as local sites109). As shown in FIG. 2, the local energy control system 200 preferablycomprises a wireless energy control unit 214 having a number of controllines 261 which carry signals for controlling the on/off states ofcontrollable switches 262. The controllable switches 262 are selectivelydisconnected and re-connected in order to effectively shut down andre-energize various local loads which are supplied by individual powerlines 263 split off from a main power line 208, which may bring incomingpower from a power utility or other primary power source. Thecontrollable switches 262 are preferably connected in series with, andinterposed between, a bank of circuit breakers 251 (of the type, forexample, as may typically be found at a local residence or commercialsite) and the various local power loads. An example of one type ofcircuit breaker is illustrated in FIG. 4, and described in more detaillater herein. The circuit breakers 251 generally act to preventexcessive current from being drawn from the incoming power line 208,thereby preventing hazardous conditions that may result, for example,from a short circuit or other such condition at the local site. Once acircuit breaker 251 has “tripped”, thereby stopping power flow to itsrespective local power load, it typically may be reset by, e.g.,activating a manual switch. While a preferred embodiment of the localenergy control system 200 involves controllable switches 262 interposedbetween circuit breakers 251 and the output power lines 263 carryingindividual power signals to various local loads, it will be appreciatedthat, in other embodiments, the circuit breakers 251 may be omitted, orother electrical components (e.g., fuses) may be present instead of orin addition to the circuit breakers 251.

The wireless energy control unit 214 preferably comprises built-inintelligence sufficient to receive commands electronically, and todisconnect and re-connect the controllable switches 262 in responsethereto. The wireless energy control unit 214 shown in FIG. 2 comprisesa communication unit 215, which preferably includes a receiver, and mayalso include a transmitter for two-way communication. The communicationunit 215 further comprises an antenna 216 for receiving wirelesscommands transmitted from a remote location (e.g., the central station102), the configuration and nature of the antenna 216 being determinedlargely by the nature of the particular wireless communicationtechnique, according to principles of antenna design well known in thefield of wireless communications. The wireless energy control unit 214also preferably includes a control circuit portion generally comprisingone or more components capable of receiving the power control commandsreceived via the communication unit 215, and selectively controlling thecontrollable switches 262 in response thereto. In a preferredembodiment, the control circuit portion comprises a communicationinterface 235, a processor 230, one or more clocks or timers 232, amemory 239, a set of switch or setting inputs 238, a display and/orindicator(s) 236, and a control register 237, and may also include thecontrol lines 261 and controllable switches 262.

In operation, the communication interface 235 of the wireless energycontrol unit 214 receives and, if desired, interprets and/or temporarilystores commands or other messages received from a remote transmitter viathe communication unit 215. The communication unit 215 may output datain a format dependent upon the wireless communication technique orprotocol employed and the level of sophistication of the receivingelectronics. For example, the communication unit 215 may output a streamof digital data bits at various intervals when information is receivedfrom the remote transmission source. The communication interface 235 mayinterpret the data output from the communication unit 215 and may beconfigured, for example, to recognize which data is valid and whichmessages are directed to the particular wireless energy control unit214. Messages transmitted from the remote transmission source (e.g.,central station 102) may, for example, and as further described herein,be addressed or encoded so that only certain wireless energy controlunits (e.g., those in a specific geographic area) react to the commandsor messages being sent.

When information arrives via the communication unit 215 andcommunication interface 235 that appears to be valid, the processor 230may become aware of the received information through any suitable means.For example, the processor 230 may receive an interrupt signal from thecommunication unit 215, or may poll the communication unit 235 regularlyto determine if information has arrived. In some embodiments, toconserve energy, it may be advantageous to allow the processor 230 andother control circuitry to be placed in a “sleep” state, wherein thecircuitry of the wireless energy control unit 214 is essentially shutdown, except for the communication unit 215 and communication interface235 and other essential circuitry, if any, by disengaging the powersupply to the wireless energy control unit 214. The processor 230 andother control circuitry is reactivated or “awakened” by re-engaging thepower supply, which may be carried out by special internal power supplymanagement circuitry (not shown) when the communication interface 235detects that information has been received via the communication unit215, or upon some other event requiring attention (e.g., programming ofsettings, display update, periodic status check, etc.). In this manner,the wireless energy control unit 214 may use only minimal power when notresponding to commands or performing some other necessary activity.

When the processor 230 has been informed that transmission has beenreceived from the remote transmitter, the processor 230 attempts torespond to any commands or other messages that may have been received.The response of the processor 230 generally may depend upon certainstored parameters and other configuration information or programminginstructions stored at the wireless energy control unit 214. In thisregard, the memory 239 may be advantageously comprised of differentlogical and/or physical portions, including a working memory portion243, a program instruction storage portion 242, and a parameter storageportion 239. Generally, the program instruction storage portion 242 andparameter storage portion 239 comprise non-volatile memory (such asEEPROM), while the working memory portion 242 comprises volatile memory(e.g., RAM). In certain embodiments, the memory 239 may also have abackup DC power source (e.g., battery) to help prevent loss of storedinformation in case the main power source is interrupted.

The program instructions stored in the program instruction storageportion 242, the parameters stored in the parameter storage portion 239,and/or the set of switch or setting inputs 238 largely dictate theresponse of the wireless energy control unit 214 to commands or othermessages received from the remote source, collectively providing rulesor logic by which the wireless energy control unit 214 determines whichcontrollable switches 262 to disconnect or re-connect. In a preferredembodiment, the wireless energy control unit 214 is user-configurable,such that the order in which the controllable switches 262 aredisengaged or re-connected can be determined individually for each localsite 109. In one aspect, the wireless energy control unit 214, incertain embodiments, provides a capability for establishing a priorityorder by which the controllable switches 262 are disengaged orre-connected. The priority order may be set by various switch or settinginputs 238 which can be manually adjusted. The switch or setting inputs238 may take any of wide variety of forms. As but one example, eachcontrollable switch 262 may be associated with a multi-position switch(not shown) providing one of the switch or setting inputs 238. Eachposition of the multi-position switch may indicate whether theassociated controllable switch 262 will be triggered in response to analert stage of a particular level, as described in more detailhereinafter. For example, in a system wherein three possible alertstages exist, the multi-position switch may have four positions, threeof which correspond to first-stage, second-stage, and third-stage alertconditions, while the fourth position indicates that the associatedcontrollable switch 262 will not respond to any of the three alertstages. The number of switch positions of the multi-position switchesmay be determined, at least in part, by the number of alert stages whichare possible.

Alternatively, the response of the controllable switches 262 to variousalert stage conditions may be software-programmable, using variousbutton/switch inputs (which may be provided as part of the switch orsetting inputs 238) for configuring the priority ordering of thecontrollable switches 262. As but one example, a user may be permittedto cycle through a routine which addresses each of the controllableswitches 262 in sequence, and for each controllable switch 262, allowsthe user to enter the desired response to an alert stage condition. Theprogramming information may be displayed on, e.g., a small LCD displayor other type of visual display (which, in FIG. 2, may generally berepresented by display/indicators 236). The wireless energy control unit214 may optionally also have a set of indicators (pictoriallyrepresented in FIG. 2 by display/indicators 236) indicating, on anindividual basis, which of the controllable switches 262, if any, aredisengaged at a given moment in time. Such indicators may be embodied,for example, as LEDs or other low-power light elements. Thedisplay/indicators 236 may also indicate (by, e.g., a special LEDindicator, or a flashing message on a small LCD display, and/or anoccasional audible sound) that an “early warning” message has beenreceived from the central station 102 indicating that a power alert isimminent.

In some embodiments, the wireless energy control unit 214 may beconfigured with a programmable timer function, allowing the priority bywhich the electrical loads are disengaged to automatically be adjustedbased upon certain timing considerations—for example, the particular dayof the week, time of day, and so on. Such timing may be programmed bythe user in the same manner as setting up the initial priority scheme bywhich the controllable switches 262 will be disengaged upon receipt ofmessages requiring such from the central station 102. The parameterstorage portion 241 of the memory 239 may store timing parameters whichcause the programmable priority of the controllable switches 262 tochange at certain specific times. The memory 239 may be configured torecord the states of the various controllable switches 262, or othersystem parameters, at various points in time. The memory 239 may, incertain embodiments, be triggered so as to record information only afteran event which causes one or more electrical loads to be disengaged, orsome other event of significance.

As further illustrated in FIG. 2, a control register 237 may be providedto store the current “command” status for the controllable switches 262.In a particular embodiment, for example, each bit of the controlregister 237 may hold a command bit whose binary state (“1” or “0”)indicates the on/off status of the associated controllable switch 262.The wireless energy control unit 214 may also be used to control otherresources in the local area—for example, a gas line shutoff 290. Themechanism for the gas line shutoff 290 may likewise have an associatedon/off status/command bit in the control register 237.

FIG. 3 is a diagram illustrating physical placement of certaincomponents utilized in one embodiment of a local energy control system.As shown in FIG. 3, a wireless energy control unit 370 may physically beattached to or placed within a circuit box 300. The circuit box 300 maycomprise a set of on/off or reset switches 351 for manually resettingcircuit breakers (e.g., circuit breakers 251 shown in FIG. 2) and/or fordisengaging, on an individual basis, the electrical loads connected toparticular circuit breaker. The switches 351 in FIG. 3 are shown invarious on and off states. Wires output from the circuit breakers forconnection to the various electrical loads may be connected via thewireless energy control unit 370 and, in particular, through the variouscontrollable switches (e.g., controllable switches 262 shown in FIG. 2)thereof. In the particular example illustrated in FIG. 3, the wirelessenergy control unit 370 is also shown with a set of manual switches 372for selecting which controllable switches will respond to remotelyissued power management instructions and in which general priority. Ifonly one power alert stage is used by the power management system 100,then the manual switches 372 can serve their function with only twoswitch positions, the first position indicating that the controllableswitch will not turn off (i.e., disconnect its electrical load) when thepower alert stage is entered, and the second position indicating that itwill turn off when the power alert stage is entered.

On the other hand, if the power management system 100 has a tiered setof power alert stages, then a more sophisticated set of switch settingsmay be employed. For example, if three power alert stages are used inthe power management system 100 (not including a “black-out” stage orother alert stages in which the local power control circuits are notinvolved), then each of the manual switches 372 may have four positions,the first three positions indicating which power alert stage is requiredbefore the corresponding controllable switch will turn off (i.e.,disengage its electrical load), and the fourth position indicating thatthe corresponding controllable switch will not turn off in response toany of the power alert stages. The fourth position may be useful formanaging electrical loads which the customer considers critical oressential and therefore does not want to be disengaged if it can beavoided.

Light indicators (e.g., LEDs) 373 next to each of the manual switches372 may be used to indicate whether any of the controllable switcheshave, in fact, disengaged their respective electrical loads in responseto a message from the central station causing the wireless energycontrol unit 370 to enter a power alert stage level requiring orrequesting local power reduction. A display and/or interface 371 may beused to present text messages, either pre-stored in the wireless energycontrol unit 370 or received from the central station, or, if buttons orsuitable means are provided, to allow programming of variouscapabilities provided by the wireless energy control unit 370.

As previously indicated with respect to the embodiment shown in FIG. 2,the wireless energy control unit 370 (and hence, the controllableswitches) may be placed either downstream or upstream from the circuitbreaker switches 351, since in either case the wireless energy controlunit 370 will be able to function so as to disengage the incoming powerwires from the local electrical loads. In one aspect, the wirelessenergy control unit 370 provides a compact, efficient and practicalmeans to regulate local power consumption, that is minimally intrusiveto the customer site because it can be integrated with a common circuitbox 300 or electrical box of similar size, therefore requiring minimalretrofitting of existing establishments.

In alternative embodiments, the wireless energy control unit 370 can beplaced in series with fuses, as opposed to or in addition to circuitbreakers.

In various embodiments, the power management system 100 operates toreduce or curtail overall customer power demand for an indefinite amountof time by issuing commands from a central source (i.e., the centralstation 102) which cause the power control circuits 112 at local sites109 individually to disengage selected electrical loads 120. In apreferred embodiment, the central station 102 issues power alert stagedeclarations based upon the amount of power demand reduction needed tomaintain operation of the power utility 105 within tolerable limits.According to one example, one or more power alert stage levels aredefined for the power management system 100, and the central station 102changes the power alert stage level by wirelessly broadcasting the alertlevel to the wireless communication units 115 at the various local sites109. As the consumer power demand increases to threshold levels at whichaction is deemed necessary, the central station 102 broadcasts the poweralert stage level appropriate to the current conditions. As the customerpower demands decrease to more tolerable levels, the central station 102may then broadcast power alert stage levels that indicate some or all ofthe electrical loads 120 may be re-engaged. The total customer powerdemand level at which various power stage alerts are declared may befixed at specific threshold levels, or at specific percentages ofoverall power capacity (which may fluctuate dynamically—e.g., day beday, hour by hour, or even more rapidly). Alternatively, the power alertstage messages may be issued in response to manual commands entered byauthorized personnel associated with the power utility 105 and/orcentral station 102, thus allowing human judgment to be involved thedecision, or a combination of automatic and manual techniques may beused. Any number of power alert stage levels may be employed, dependingupon the desired complexity of the power management system 100.

According to one example, the power management system 100 may have fourpower alert stage levels—three of which cause the local sites 109 toreduce their power consumption in response to commands received from thecentral station 102, and a fourth power alert stage level which requiresadditional steps to be taken (e.g., intentional brown out or black outof a geographical region). FIG. 11 is a state diagram 1100 illustratingthe transition between various power alert stages, according to such anexample. As illustrated in FIG. 11, the state diagram 1100 includes aplurality of states 1105 through 1109 corresponding to different poweralert stage levels. When total customer power demand is in a tolerablerange (i.e., the total customer power demand level is below a specifiedfirst threshold level designated LEVEL1), the power management system100 is kept in a non-alert state 1105. When the total customer powerdemand level exceeds the first threshold level (i.e., LEVEL1), the powermanagement system 100 enters a first stage alert state 1106, whereuponthe central station 102 broadcasts a wireless message to the localwireless communication units 115 indicating that a first stage poweralert has been declared. In response, the power control circuits 112 atthe local sites 109 selectively disengage various local electrical loads120, thus reducing the overall customer power demand to keep the totalenergy usage within a tolerable level. The power utility 105 may measurethe extent to which the power demand has dropped and convey thisinformation to the central station 102 (or other processing center) foruse in future determinations of power alert stage levels. For example,the central station 102 (or other processing center) may treat thecurrent total power demand level as including the amount by which thetotal power demand level dropped as a result of issuing the power alertstage warning, because retracting the power alert stage warning at anypoint would presumably result in the re-engagement of the previouslydisengaged local electrical loads 120 and consequent increase in totalpower demand. Therefore, when the total customer power level is shown inFIG. 11 as being compared to various threshold levels, preferably thepower management system 100 takes into account the effect of thedisengaged local electrical loads 120.

So long as the total customer power demand stays above the first demandthreshold LEVEL1 but below a second demand threshold LEVEL2, the powermanagement system 100 stays in the first stage alert state 1106.However, if the total customer power demand continues to increase suchthat it passes the second demand threshold LEVEL2, the power managementsystem 100 then enters a second stage alert state 1107, and the centralstation 102 wirelessly broadcasts a message to the wirelesscommunication units 115 at the various local sites 109 indicating that asecond stage power alert warning has been declared. On the other hand,however, if the total customer power demand drops back below the firstdemand threshold LEVEL1, the power management system 100 returns to thenon-alert state 1105, whereupon the central station 102 wirelesslybroadcasts a message to the wireless communication units 115 at thevarious local sites 109 indicating that the first stage power alert isno longer in affect, and that the power management system 100 isreturning to the non-alert state 1105.

So long as the total customer power demand stays above the second demandthreshold LEVEL2 but below a third demand threshold LEVEL3, the powermanagement system 100 stays in the second stage alert state 1107.However, if the total customer power demand continues to increase suchthat it passes the third demand threshold LEVEL3, the power managementsystem 100 then enters a third stage alert state 1108, and the centralstation 102 wirelessly broadcasts a message to the wirelesscommunication units 115 at the various local sites 109 indicating that athird stage power alert warning has been declared. On the other hand, ifthe total customer power demand drops back below the second demandthreshold LEVEL2, the power management system 100 returns to the firststage alert state 1106, whereupon the central station 102 wirelesslybroadcasts a message to the wireless communication units 115 at thevarious local sites 109 indicating that the second stage power alert isno longer in affect, and that the power management system 100 isreturning to the first stage alert state 1106.

Similarly, so long as the total customer power demand stays above thethird demand threshold LEVEL3 but below a fourth demand thresholdLEVEL4, the power management system 100 stays in the third stage alertstate 1108. However, if the total customer power demand continues toincrease such that it passes the fourth demand threshold LEVEL4, thepower management system 100 then enters a fourth stage alert state 1109,whereupon additional steps are taken (e.g., regional black out or brownout). No wireless commands are necessary in such a situation; however, ablackout or brownout warning message may, if desired, be transmitted bythe central station 102, so that customers at the local sites 109 canobtain a warning before a blackout or brownout occurs. Optionally, theapproximate amount of time until the blackout or brownout may also betransmitted by the central station 102, and the time until the upcomingoutage event may be displayed by the local power control circuits 112 sothat the customers might take whatever steps are desired in such asituation. When the total customer power demand drops back below thethird demand threshold LEVEL3, the power management system 100 returnsto the second stage alert state 1107, whereupon the central station 102wirelessly broadcasts a message to the wireless communication units 115at the various local sites 109 indicating that the third stage poweralert is no longer in affect, and that the power management system 100is returning to the second stage alert state 1107.

As an alternative way of achieving a similar result, a single powerusage threshold may be used, and the amount by which customer powerdemand drops in response to each power alert stage level is notnecessarily considered in the calculation of the next power alert stagelevel. According to this alternative embodiment, as each power alertstage level is declared, the total customer power demand level isexpected to drop due to the collective effect of the various energycontrol units 114 at the various local sites 109. Therefore, the samepower usage threshold may be used for each power alert stage level whileallowing the beneficial operation of the power management system 100.For example, the power usage threshold may be set at 96% of total powercapacity. When total customer power demand reaches the power usagethreshold, a first stage power alert warning message is transmitted tothe wireless energy control units 114, which disengage some of theelectrical loads 120. As a result, total customer power demand will dropby some amount (for example, five percent). The power usage thresholdmay remain at 96% of capacity. When total customer power demand reaches96% again during the first power alert stage level, the central station102 may then transmit a second stage power alert warning message to thewireless energy control units 114, thereby causing another drop in totalcustomer power demand. This cycle may be repeated for entry into thethird and fourth power alert stage levels.

The process 1100 may be implemented in an automated system using, forexample, one or more computer processors to carry out, which may belocated at the central station 102 or elsewhere, in either a centralizedor distributed architecture. The threshold levels between the variouspower alert stages may be programmable. A hysteresis technique may beused such that when the customer power demand is near a threshold level,the system does not switch back and forth between two different poweralert stage levels too quickly. In other words, when the customer powerdemand is increasing, the threshold level may be increased by ahysteresis amount, and as soon as the threshold level (plus thehysteresis amount) is passed and a new alert stage level entered, thethreshold level may be decreased by a hysteresis amount so that as thecustomer demand level decreases it needs to drop below the thresholdlevel minus the hysteresis amount in order to switch back to the lowerpower alert stage level. Also, since switching to the next power alertstage level is expected to cause the total customer power demand to droprather suddenly (although such an effect can be mitigated by adding thedrop-off amount into the total customer power demand level used forpower alert stage calculations, as alluded to above), a hysteresistechnique is helpful to prevent a rapid switch back to the previouspower alert stage level as soon as the local sites 109 start sheddingtheir selected electrical loads 120.

Applying the techniques illustrated in FIG. 11, a power utility 102 maybe able to control dynamically the total customer power demand, and thusreduce peak customer power consumption when necessary to avert a powercrisis. By providing multiple alert stage levels, such a powermanagement technique allows some granularity in selecting the amount ofcustomer power to be reduced, and places the minimal burden necessary onthe customers.

Further description will now be provided concerning various ways inwhich a local power control circuit may selectively disconnect orre-connect controllable switches in order to effectuate control of localpower consumption. This description will focus on the embodiment of alocal energy control system 200 illustrated in FIG. 2, but theprinciples and concepts are applicable to other embodiments as well.Assuming a power management system in which different power alert stagesare defined, when the local energy control system 200 receives a messageto enter the next highest power alert stage, the wireless energy controlunit 214 examines the switch or setting inputs 238 and/or storedparameters 241 in order to determine which controllable switches 262 todisengage. In the example in which the switch or setting inputs 238 areestablished by multi-position switches such as previously described(with each switch position corresponding to the power alert stage atwhich the corresponding controllable switch 262 will respond by sheddingits respective electrical load), the processor 230 may simply examinethe position settings of each of the multi-position switches todetermine whether or not the corresponding controllable switch 262should be set to an open position so as to disconnect its respectiveelectrical load. When a message from the central station 102 instructsthe wireless energy control unit 214 to enter a first power alert stage,for example, the processor 230 checks the switch setting of each of themulti-position switches to determine whether the switch positionindicates a response to the first power alert stage. When a message fromthe central station 102 instructs the wireless energy control unit 214to enter a second power alert stage, the processor 230 checks the switchsetting of each of the multi-position switches to determine whether theswitch position indicates a response to either the first power alertstage or second power alert stage. When a message from the centralstation 102 instructs the wireless energy control unit 214 to enter athird power alert stage, the processor 230 checks the switch setting ofeach of the multi-position switches to determine whether the switchposition indicates a response to either the first power alert stage,second power alert stage or third power alert stage. In each case, whenthe processor 230 determines that a controllable switch 262 shouldrespond to the current power alert stage level, the processor 230 issuesthe appropriate command in the control register 237, which in turncauses the corresponding controllable switch 262 to open and disengageits electrical load.

In an alternative embodiment, the switch or setting inputs 238 indicatea relative priority for disengaging the controllable switches 262 inresponse to remote commands from a central station 102. In such anembodiment, an indeterminate number of power alert stages may beutilized. When the first power alert stage message (or power reductioncommand) is received, the controllable switch 262 with the lowestpriority is opened and its electrical load thereby disengaged. With eachsubsequent power alert stage message (or power reduction command), thenext highest priority controllable switch 262 is opened, until, at amaximum, all of the controllable switches 262 are opened. However, theswitch or setting inputs 238 may also indicate that certain controllableswitches 262, which may correspond to, e.g., critical or essentialelectrical devices, are to remained closed continuously and neveropened.

Alternatively, if the wireless energy control unit 214 is connected tothe output reading from a local power meter so that it can dynamicallymonitor how much power is being used at the local site, the wirelessenergy control unit 214 may be instructed (either directly orindirectly), or pre-programmed, to reduce local power consumption by aspecified percentage or amount. The wireless energy control unit 214 maythen make an initial determination (according to techniques describedabove, for example) of which electrical loads to shed and, thus, whichcontrollable switches 262 initially to open. The wireless energy controlunit 214 may then monitor the local power usage to determine ifadditional controllable switches 262 need to be opened to either reachthe desired target energy usage level or maintain energy usage at thedesired target level. The wireless energy control unit 214 may open upthe additional controllable switches 262 in the priority that isindicated by the switch or setting inputs 238.

As the level of the power alert stages is decreased, the wireless energycontrol unit 214 may close the controllable switches 262 and therebyre-engage the electrical loads in the reverse order in which thecontrollable switches 262 were opened. The wireless energy control unit214 may, if desired, impose a time delay between the re-connection ofany two controllable switches 262 to reduce the possibility of powerspikes or similar undesirable effects.

FIGS. 12 and 13 are process flow diagrams illustrating various stepsinvolved in transitioning between different alert stages, according totwo different embodiments as disclosed herein. While the processes inFIGS. 12 and 13 are described below for convenience with reference tothe power management system embodiment shown in FIG. 1, it will beunderstood that the principles and concepts are applicable to otherpower management system embodiments as well. Turning first to FIG. 12, aprocess 1200 for power management in accordance with a first embodimentis illustrated. In the process 1200 shown in FIG. 12, it is assumed thatthe central station 102 has already determined, based upon the criteriaused to make such a determination, that a message is to be transmittedwirelessly to the various local sites 109 in order to adjust their powerconsumption (or, in certain cases, for some other purpose). Thus, in afirst step 1201, the central station 102 transmits a message (or seriesof messages), via its wireless communication unit 103, to the wirelesscommunication units 115 at the various local sites 109.

The wireless transmission from the central station 102 may take any of avariety of forms. For example, the wireless transmission may comprise abroadcast transmission intended for receipt at all of the local sites109. Alternatively, it may comprise a broadcast transmission intendedfor receipt at only certain specified local sites 109. In this regard,the local sites 109 may, if desired, be organized into different groups,according to any logical criteria, such as geographic region,residential/commercial (possibly with different sub-categories ofresidential and/or commercial), average usage, etc., or any combinationthereof. Local sites 109 in a particular group may be instructed by thecentral station 102 through broadcast messages which are specificallytargeted for that group. Each group of local sites 109 may, for example,be assigned a unique group address or group instruction code, and eachlocal site 109 then responds only to its unique group address or groupinstruction code. Alternatively, or in addition, each group of localsites 109 may be assigned a unique frequency band or sub-band or aunique encoding scheme, and each local site 109 would then have itswireless communication unit 115 attuned to its unique frequency band orsub-band or configured to receive and decode messages according to itsunique encoding scheme. In this manner, the central station 102 isprovided with increased flexibility of power management, allowing thecentral station 102 to command all or any group of local sites tocurtail power consumption. As one benefit of such an arrangement, thecentral station 102 may command only a few groups of local sites 109 tocurtail power in response to a power demand situation and, only if theamount of power reduced is insufficient, increase the scope of the powerreduction request to other groups in gradual steps until the desiredamount of power reduction is reached.

In addition to a group address or code for groups of local sites 109,each local site 109 can also be assigned an individual address or codewithin its group, thereby allowing each local site 109 to beindividually commanded if desired. Also, one of the group addresses orcodes (or frequency bands or sub-bands, or encoding schemes) may be asystemwide broadcast address or code, allowing the central station 102to reach all of the local sites 109 through a single command or sequenceof commands which are designated with the systemwide broadcast addressor code.

Returning now to FIG. 12, in a next step 1205, the wirelesscommunication units 115 at the various local sites 109 receive themessage transmitted from the central station 102. In the following step1208, each local site 109 decodes or otherwise recovers or re-constructsthe information in the received message and, if the message is intendedfor the particular local site 109, parses the received message into anyconstituent components. If group addressing or coding is used, forexample, the power control circuit 112 at a particular local site 109may obtain group address or code information (e.g., in a specific field)from the received message, and may thereby determine whether thereceived message is intended for the particular local site 109 bycomparing the group address or code in the received message with thelocal site's own group address or code. The local site 109 may likewisedetermine whether the received message is a systemwide broadcast messageintended for all of the local sites 109 within the power managementsystem 100, by comparing the group address or code with a systemwidebroadcast address or code.

Assuming the message is intended for it, the local site 109 parses themessage in order to determine the nature of the communication receivedfrom the central station 102. As examples of messages that might bereceived, the local site 109 may receive a message instructing it toenter the next highest stage of power alert, to enter the next loweststage of power alert, to adjust a parameter, or to take some otheraction (e.g., display a power alert stage warning message). Variousother message types may also be employed. If the received messageinstructs the power control circuit 112 at the local site 109 to enterthe next highest stage of power alert, then, in step 1236, the powercontrol circuit 112 determines which power control switch or switches(such as switches 262 in FIG. 2) should be opened and thereby whichlocal electrical loads 120 to shed. Examples of how this determinationmay be made are described with respect to FIGS. 2 and 3, and elsewhereherein. In step 1238, the desired power control switch or switches areopened and, in step 1250, the various status indicators (e.g., LEDs) areupdated. For example, an LED may be illuminated next to each powercontrol switch that has been disengaged. Other status indication meansmay also be used; for example, an audible sound may be issued by thepower control circuit 112 to indicate to the customer that one or moreelectrical loads 120 have been temporarily shed.

If, on the other hand, the received message instructs the power controlcircuit 112 to enter the next lowest stage of power alert, then, in step1240 (and assuming the power control circuit 112 is not in the non-alertstage), the power control circuit 112 determines which power controlswitch or switches should be closed and thereby which local electricalloads 120 to re-connect to power lines 108. Examples of how thisdetermination may be made are described with respect to FIGS. 2 and 3,and elsewhere herein. In step 1243, the desired power control switch orswitches are closed and again, in step 1250, the various statusindicators (e.g., LEDs) are updated. For example, an LED next to eachpower control switch that has been re-connected may be turned off.

If the received message neither instructs entry into the next higheststage of power alert nor instructs entry into the next lowest stage ofpower alert, then in step 1225 the message is interpreted by the powercontrol circuit 112 and acted upon. The specific action depends upon thenature of the received message. For example, if the message is a warningthat a power alert is expected, the power control circuit 112 maydisplay a message indicated such (along with the amount of time untilthe expected power alert, if desired) and/or make an audible noiseindicating that a message of interest has been received.

If the power control circuit 112 is actively adjusting the power controlswitches that are opened and closed by, e.g., monitoring powerconsumption at the local site 109 (via a local meter, for instance),then the process 1200 may be modified such that a feedback loop iseffectuated, wherein the power control circuit 112 continuouslydetermines the power control switch settings, adjusts the power controlswitch settings, and updates the status indicators. Where activemonitoring and adjustment of local power consumption occurs, the powercontrol circuit 112 may open and close power control switches atdifferent times at any given power alert stage. The power controlcircuit 112 may, in such an embodiment, be configured so as to limit thefrequency of opening or closing power control switches, so as tominimize inconvenience to the local customer.

FIG. 13 illustrates another process 1300 for power management similar tothe process 1200 illustrated in FIG. 12 but with certain modifications.In FIG. 13, steps 1301, 1305 and 1308 are generally analogous to steps1201, 1205 and 1208 in FIG. 12. Likewise, steps 1336, 1338, 1340, 1343and 1350 are generally analogous to the corresponding steps illustratedin FIG. 12. However, in FIG. 13, new steps 1330, 1332 and 1335 are addedover the process 1200 shown in FIG. 12. The added steps to the process1300 of FIG. 13 address a situation in which entry into the next highestpower alert stage is to be delayed for an amount of time specified bythe central station 102. In such a situation, according to theembodiment illustrated in FIG. 13, when the power control circuit 112has determined that the received message instructs entry into the nexthighest power alert stage, the power control circuit 112 also derivesfrom the received message an indication of whether entry into the nexthighest power alert stage is immediate or delayed and, if delayed, theamount of time until the power alert stage is entered. If entry into thenext highest power alert stage is immediate, then the process 1300 movesdirectly to step 1336. If entry into the next highest power alert stageis delayed, then in step 1332 the power control circuit 112 issues awarning, which may take the form of, for example, illuminating a warninglight, issuing an audible sound or sound pattern, or the like. The powercontrol circuit 112 then waits for timeout of the delay period, asindicated by step 1335, before moving on to step 1336 after the delayperiod is over. The power control circuit 112 may use an internal timeror clock to measure the delay period to effectuate the foregoingoperation.

FIG. 10 is a diagram illustrating various components of a local energycontrol system 1012 in relationship to one another, in accordance withone embodiment as disclosed herein, illustrating the potential use offeedback from a local meter 1092 for determining, at least in part,operation of the controllable switches 1062. As illustrated in FIG. 10,a set of switch controls 1037 are used to control the settings of aplurality of controllable switches 1062 which, similar to thecontrollable switches described with respect to FIGS. 2 and 3, allowselective connection and disconnection of local electrical loads. Alocal power meter 1092 monitors the power drawn on the incoming powerlines 1008 (or alternatively, the outgoing power lines 1063), andoutputs a power usage measurement signal which is provided to anevaluator 1030 (which may be embodied as a processor operating accordingto stored program instructions and various inputs). The evaluator 1030compares the power usage measurement with a power usage target 1094 todetermine whether additional ones of the controllable switches 1062should be opened or closed. The power usage target 1094 is preferablyset based upon power alert stage level 1093 of the local energy controlsystem 1012. If the evaluator 1030 determines that, based upon the powerusage measurement, local power consumption exceeds the power usagetarget 1094, then the evaluator 1030 determines which controllableswitches 1062 to open or close based upon the priority settings 1038which, as discussed earlier, can be set manually or programmed via aninterface 1029. As power commands 1017 are received from a centralstation, the evaluator 1030 updates the power alert stage level 1093 andthe power usage target 1094 as required. The local energy control system1012 thereby provides a level of robust control of power consumption ata local site, and can be utilized advantageously in a power managementsystem such as shown in FIG. 1 to effectuate overall power demandreduction when required by a power utility.

FIG. 9 is a block diagram of an embodiment of a local energy controlsystem 900 illustrating principles that may be employed, for example, inconnection with various power management systems as disclosed herein,and illustrating, among other things, a mechanism for providing power tothe local energy control system 900. As shown in FIG. 9, the localenergy control system 900 comprises an energy controller 910 by whichvarious controllable switches 962 may be used to selectively disconnectpower from incoming power line(s) 908 to various local loads,graphically represented in FIG. 9 as inductive elements 919. Aspreviously described herein with respect to FIGS. 2 and 3, for example,the controllable switches 962 may be connected in series with (e.g.,interposed between) circuit breakers 951 (or other similar electricaldevices) and the various local loads. A decoupler 911 is preferably usedto allow power to be supplied from the incoming power line(s) 908 to theenergy controller 910. In a preferred embodiment, the decoupler 911comprises a capacitor (possibly in combination with other circuitelements), although in alternative embodiments the decoupler 911 maycomprise a transformer and, if appropriate, supporting circuit elements.

In alternative embodiments, power may be supplied to the energycontroller 910 indirectly, such as from an output of one of the circuitbreakers 951 (preferably one that does not have a controllable switch962 and therefore cannot be disconnected).

The nature of the power signal on the incoming power line(s) 908 (ormore generally, power lines 108 in FIG. 1) depends in part on the typeof user. Large industrial consumers (e.g., railroads) might accept powerdirectly at voltage levels of 23 to 138 kV, and typically step down thevoltages further. Smaller industrial or commercial consumers typicallyaccept power at voltage levels of 4.16 to 34.5 kV. Residential consumersor light commercial users normally receive power from local distributiontransformers at nominal voltage levels of 120 and/or 240 Volts. Powerreceived by residential consumers or light commercial users is typicallysingle-phase, alternating current (AC) in nature, with a nominalfrequency of about 60 Hertz. The illustrative values described above aretypical in the United States, but may vary in other parts of the world.

Certain preferred controllable electronic switches as may be used atlocal sites in connection with various power management systems asdisclosed herein, and in particular various local energy control units,will now be described. First, however, is presented a comparison ofpreferred controllable electronic switches with conventional electricalcomponents and, in particular, bi-metal based circuit breakers.

FIG. 4 is a conceptual diagram of a bimetal-based circuit breaker 400 asknown in the art. As illustrated in FIG. 4, the circuit breaker 400comprises a bimetal arm 401 which is formed of two metallic layers 402,403. The bimetal arm 401 is anchored at one end 406, and connects atthat end 406 to an incoming power signal line 415. At its other end 407,the bimetal arm 401 resides in electrical contact with an electricalconductor 420. The electrical conductor 420 may be connected to a load(not shown) and, in normal operation (i.e., normal current flow), powerfrom the power signal line 415 is conducted through the bimetal arm 401and the electrical conductor 420 to the load.

The metallic substances of the different metallic layers 402, 403 of thebimetal arm 401 are selected to have different thermal properties suchthat they heat at different rates. In particular, the metallic substanceof the lower metallic layer 402 heats faster than the metallic substanceof the upper metallic layer 403. When the amount of current travelingthrough the bimetal arm 401 is within “normal” limits, the amount ofheating caused by the current passing through the bimetal arm 401 (whichhas a natural resistivity) is small and the bimetal arm 401 does notdeform. However, when the amount of current traveling through thebimetal arm 401 exceeds an over-current limit (which is determinedlargely by the relative thermal properties of the metallic substancesused in the metallic layers 402 and 403), the lower metallic layer 402heats more rapidly than the upper metallic layer 403 and causes thebimetal arm 401 to bend, thus breaking the electrical circuit pathbetween the incoming power signal line 415 and the electrical conductor420.

This operation can be illustrated by the diagrams of FIGS. 5-1 and 5-2.FIG. 5-1 is a diagram illustrating an example of the flow of electricitywhen the circuit breaker 400 of FIG. 4 is closed (normal operation), andFIG. 5-2 is a diagram illustrating an example of how the bimetal arm 401of the circuit breaker 400 breaks the circuit connection when anover-current situation occurs. As shown in FIG. 5-1, a power signaltravels through incoming power wire 415 (marked “IN”) through thebimetal arm 401 and across contacts 412, to the electrical conductor 420(marked “OUT”). So long as the amount of current in the power signal isbelow the over-current limit, the amount of heating caused by thecurrent passing through the bimetal arm 401 is small, and the bimetalarm 401 does not deform. However, as now shown in FIG. 5-2, when theamount of current traveling through the bimetal arm 401 exceeds theover-current limit, the current heats the bimetal arm 401, but the lowermetallic layer 402 heats more rapidly than the upper metallic layer 403thus causing the bimetal arm 401 to bend. As a result, the contacts 412gradually separate, breaking the electrical circuit path between theincoming power signal line 415 and the electrical conductor 420. Theamount of current needed to cause the circuit breaker 400 to “trip”depends upon the relative thermal properties of the two metallic layers402, 403 of the bimetal arm 401.

After being tripped, gradually the bimetal arm 401 of the circuitbreaker 400 will cool, until eventually the bimetal arm 401 is no longerdeformed. As this occurs, the contacts 412 once again form an electricalconnection, allowing the power signal to pass from the incoming powerwire 415 to the electrical conductor 420.

FIG. 6 is a diagram of a controllable electronic switch 600 as may beused, for example, in certain embodiments of power distribution andmanagement systems and methods, and local energy control units, asdescribed herein. As shown in FIG. 6, the controllable electronic switch600 comprises a deformable member 601 which may be formed in the generalshape of an arm (similar to that shown in FIG. 4) and may be comprisedof two layers 602, 603 having different thermal properties. Preferably,the two layers 602, 603 are metallic in nature, although any durablesubstance that bends when heated can be used. As further shown in FIG.6, the deformable member 601 is preferably anchored at one end 606 to anon-conductive surface 615. At its other end, the deformable member 601preferably resides in contact with an electrical conductor 620 throughcontacts 612. An incoming power wire 625 is connected to the deformablemember 601 preferably near the contact point with the electricalconductor 620, so as to minimize any power dissipation caused by thecurrent running through the deformable member 601, and also so as toavoid heating the deformable member 601 to any significant degreeregardless of the current being drawn. The electrical conductor 620 maybe connected to a load (not shown) and, in normal operation (that is, inthe absence of assertion of a switch control signal, as explainedbelow), power from the power signal line 625 is conducted through thedeformable member 601 and the electrical conductor 620 to the load.

The metallic substances of the different metallic layers 602, 603 of thedeformable member 601 are preferably selected to have different thermalproperties such that they heat at different rates. In particular, themetallic substance of the lower metallic layer 602 preferably heatsfaster than the metallic substance of the upper metallic layer 603. Whenheat is applied to the deformable member 601, the faster heating of thelower metallic layer 602 as compared to the upper metallic layer 603causes the deformable member 601 to bend, similar to a circuit breaker400, thus breaking the electrical circuit path between the incomingpower signal line 625 and the electrical conductor 620.

As further illustrated now in FIG. 6, a heating element 645 (such as aresistive coil) is coupled (e.g., wrapped around, in the case of aresistive coil) to the deformable member 601. The heating element 645 ispreferably controlled by a switch control circuit 640 connected theretoby a pair of signal lines 641, 642. When the switch control signaloutput from the switch control circuit 640 is not asserted, the heatingelement 645 is effectively disconnected (and thus inactive), and poweris delivered through the incoming power wire 625 across the end 607 ofthe deformable member 601, via contacts 612, to the electrical conductor620, from which it can be further distributed to the load. Thisoperation is illustrated in FIG. 7-1. When, however, the switch controlsignal from the switch control circuit 640 is asserted, the heatingelement 645 heats up due to the effect of the current flowing throughthe heating element 645. Since the lower metallic layer 602 heats morerapidly than the upper metallic layer 603, the deformable member 601starts to bend bends. Eventually, as a result of this bending, thecontacts 612 gradually separate, breaking the electrical circuit pathbetween the incoming power signal line 625 and the electrical conductor620, as illustrated in FIG. 7-2.

So long as the switch control signal from the switch control circuit 640is asserted, the heating element 645 continues to keep the deformablemember 601 bent and the electrical path between the incoming power wire625 and the electrical conductor 620 disconnected. Once the switchcontrol signal from the switch control circuit 640 is de-asserted, thedeformable member 601 gradually cools, until eventually the deformablemember 601 is no longer deformed. As this occurs, the contacts 612 onceagain form an electrical connection, allowing the power signal to passfrom the incoming power wire 625 to the electrical conductor 620 andthen to the load.

In one aspect, the controllable electronic switch 600 illustrated inFIG. 6 can provide a convenient, inexpensive mechanism for controllingthe distribution of power from a source to a load. Moreover, thecontrollable electronic switch 600 need not consume any power when thedeformable member 601 is in a closed position, and only requires minimalpower to cause the deformable member 601 to open.

The incoming power wire 625 may be connected to the deformable member601 in any of a variety of manners. The incoming power wire 625 may, forexample, simply be welded, spliced or soldered to the moving end 607 ofthe deformable member 601. Any form of attaching the incoming power wire625 to the deformable member 601 will suffice so long as electricityconducts between the incoming power wire 625 and the electricalconductor 620 when the deformable member 601 is in a switch-closedposition.

FIG. 8 is a block diagram illustrating a more general embodiment of acontrollable electronic switch 800. As illustrated in FIG. 8, thecontrollable electronic switch 800 comprises a deformable member 801which controllably connects an incoming power wire 825 to an electricalconductor 820. A heating element 845 is coupled to the deformable member801, and is controlled by a switch control circuit 840. The deformablemember 801, which may take the form of, e.g., a bimetal member or arm,preferably allows the incoming power wire 825 to conduct a power signalto the electrical conductor 820 when the deformable member 801 is notbeing heated by the heating element 845, but preferably causes theconnection between the incoming power wire 825 to the electricalconductor 820 to be physically broken when then deformable member 801 isheated by the heating element 845. The heating element 845 may comprise,e.g., a resistive coil or other resistor, and, if a resistive coil, maybe conveniently wound around the deformable member 801 if embodied as abimetal member or arm.

In either of the embodiments illustrated in FIGS. 6 and 8, thedeformable member 601 or 801 need not be uniformly straight and, infact, can be any shape so long as, when heated, it bends in apredictable manner so as to break the electrical connection between theincoming power wire 625 or 825 and the electrical conductor 620 or 820.Moreover, although the deformable member 601 or 801 is described in apreferred embodiment as a bimetal arm having two metallic layers, italternatively could be made out of any other material (metallic orotherwise) that bends in a predictable manner. Because no current needsto travel from one end of the deformable member 601 or 801 to the otherend (unlike a circuit breaker), the deformable member 601 or 801 may, ifdesired, have non-conductive or insulating portions separating thevarious areas of the deformable member 601 or 801 from one another. Forexample, a non-conductive portion (e.g., plastic) could be placedbetween the area of the deformable member 601 or 801 coupled to theheating element 645 or 845 and either end of the deformable member 601or 801 (e.g., either end 606 and/or 607 of the deformable member 601 inthe example of FIG. 6). Further, the end of the deformable member 601through which power is conducted (e.g., end 607 in FIG. 6) need not bebimetal, but could be a uniform conductive material (e.g., a singlemetal). Alternatively, the deformable member 601 or 801 could haveadditional (i.e., more than two) layers. The primary quality of thedeformable member 601 or 801 is that it bends or otherwise deformssufficiently when heated so as to break the electrical connection of thepath of the power signal (e.g., by separating contacts 612 in theexample of FIG. 6).

The switch control signal output from the switch control circuit 640 or840 to the heating element 645 or 845 is preferably a direct current(DC) signal, but could also be an alternating current (AC) signal orhybrid signal. When the switch control signal is not asserted, theswitch control circuit 640 may simply short the heating element 645 or845 (e.g., by shorting wires 641, 642 in the example of FIG. 6), or elsesimply isolate the heating element 645 or 845 through a buffer or otherisolation circuit.

While the heating elements 645 and 845 in FIGS. 6 and 8 have beendescribed in preferred embodiments as a resistive coil, the heatingelement 645 or 845 could take other forms or configurations. Forexample, if embodied as a resistive coil, the heating element 645 or 845need not be wound around the deformable member 601 or 801. The heatingelement 645 or 845 could be a different type of resistor besides aresistive coil. However, a resistive coil is preferred as the heatingelement 645 or 845 because it provides relatively even heating over agiven area, and is relatively simple to implement and is relativelyinexpensive.

The speed of response of the deformable member 601 or 801 to the switchcontrol circuit 640 or 840 may or may not be critical, depending uponthe particular application. If the speed of response is not verycritical, then the switch control signal can be a very low power signal.If faster response time is desired, the switch control signal can beincreased in power, thus causing more rapid heating of the heatingelement 645 or 845. The switch control circuit 640 or 840 may beprovided with its own power source (e.g., a battery), or else it mayobtain power from the incoming power wire 625 or 825 or some otheravailable source. The switch control circuit 640 or 840 may be activatedby a manual switch (not shown) which causes assertion of the switchcontrol signal and, therefore, eventual opening of the controllableelectronic switch 600 or 800, or else may be activated by a remoteelectronic signal.

FIG. 14 is a diagram of another embodiment of a controllable electronicswitch 1400 using a wedge to physically break electrical contacts in acircuit path. As illustrated in FIG. 14, the controllable electronicswitch 1400 comprises a generally elongate deformable member 1401 whichis formed of two layers 1402, 1403, similar in nature to the deformablemember 601 described previously with respect to FIG. 6. In a preferredembodiment, the deformable member 1401 comprises a bimetal arm, and thetwo layers 1402, 1403 are metallic in nature, although more generallythe two layers 1402, 1403 may be comprised of any suitable materialshaving sufficiently different thermal properties to carry out thefunctions described herein. The deformable member 1401 is preferablyanchored at one end 1406 to a non-conductive surface 1405. At its otherend, the deformable member 1401 has a wedge-shaped member 1451.

As further illustrated in FIG. 14, narrow end of the wedge-shaped member1451 resides in close proximity to a pair of electrical contacts 1452.The pair of electrical contacts 1452 reside in contact with a pair ofelectrical conductors 1420, 1425, the first electrical conductor 1425serving as an incoming power wire and the second electrical conductor1420 serving as a power delivery means to a load (not shown). In normaloperation, power from the first electrical conductor 1425 is conductedthrough the electrical contacts 1452 to the second electrical conductor1420 and thereby to the load. The electrical contacts 1452 are attachedto a pair of non-conductive arms 1457, which are anchored to a stablesurface 1460. A pair of springs 1455 or other such means applies forceto the non-conductive arms 1457 and thereby maintains the electricalcontacts 1452 in contact in normal operation.

The electrical path formed across the electrical contacts 1452 may bebroken by application of a control signal to the deformable member 1401.To this end, a heating element 1445 (such as a resistive coil) iscoupled to the deformable member 1401 (e.g., wrapped around thedeformable member 1401, where embodied as a resistive coil). The heatingelement 1445 is preferably controlled by a switch control circuit 1440connected thereto by a pair of signal lines 1441, 1442. When the switchcontrol signal output from the switch control circuit 1440 is notasserted, the heating element 1445 is effectively disconnected (and thusinactive), and power is delivered through the incoming power wire 1425across the electrical contacts 1452 to the electrical conductor 1420,from which it can be further distributed to the load. When, however, theswitch control signal from the switch control circuit 1440 is asserted,the heating element 1445 heats up due to the effect of the currentflowing through the heating element 1445. Similar to the deformablemember 601 previously described with respect to FIG. 6, the deformablemember 1401 of controllable electronic switch 1400 starts to bend.Eventually, as a result of this bending, the wedge 1451 if forcedbetween the electrical contacts 1452, causing the contacts 1452 togradually separate (with springs 1455 gradually compressing), andbreaking the electrical circuit path between the incoming power signalline 1425 and the electrical conductor 1420, as illustrated in FIG. 15.

So long as the switch control signal from the switch control circuit1440 is asserted, the heating element 1445 continues to keep thedeformable member 1401 bent and the electrical path between the incomingpower wire 1425 and the electrical conductor 1420 disconnected. Once theswitch control signal from the switch control circuit 1440 isde-asserted, the deformable member 1401 gradually cools, untileventually the deformable member 1401 is no longer deformed. As thisoccurs, the wedge 1451 gradually retracts, causing the electricalcontacts 1452 to come together and once again form an electricalconnection, which in turn allows the power signal to pass from theincoming power wire 1425 to the electrical conductor 1420 and then tothe load.

In one aspect, the controllable electronic switch 1400 illustrated inFIG. 14, like the controllable electronic switch 600 of FIG. 6, canprovide a convenient, inexpensive mechanism for controlling thedistribution of power from a source to a load. Moreover, thecontrollable electronic switch 1400 need not consume any power when theelectrical contacts 1452 are in a closed position, and only requiresminimal power to cause the deformable member 1401 to bend and theelectrical contacts 1452 to spread apart, opening the power signalcircuit path.

FIG. 16 is a diagram of another embodiment of a controllable electronicswitch 1600 using a wedge-shaped member to break electrical contacts ina circuit path. Many of the components shown in FIG. 16 are similar innature to those illustrated in FIG. 14. Thus, for example, thecontrollable electronic switch 1600 of FIG. 16 comprises a generallyelongate deformable member 1601 which is formed of two layers 1602,1603, similar in nature to the deformable member(s) 601, 1401 describedpreviously with respect to FIGS. 6 and 14, respectively. In a preferredembodiment, the deformable member 1601 comprises a bimetal arm, and thetwo layers 1602, 1603 are metallic in nature, although more generallythe two layers 1602, 1603 may be comprised of any suitable materialshaving sufficiently different thermal properties to carry out thefunctions described herein. The deformable member 1601 is preferablyanchored at one end 1606 to a non-conductive surface 1605. At its otherend, the deformable member 1601 has a wedge-shaped member 1651 that, aswill be described in more detail below, functions as a mechanical cam.

As further illustrated in FIG. 16, one end of the wedge-shaped member1651 resides in close proximity to a pair of electrical contacts 1652.The pair of electrical contacts 1652 reside in contact with a pair ofelectrical conductors 1620, 1625, the first electrical conductor 1625serving as an incoming power wire and the second electrical conductor1620 serving as a power delivery means to a load (not shown). In normaloperation, power from the first electrical conductor 1625 is conductedthrough the electrical contacts 1652 to the second electrical conductor1620 and thereby to the load. The electrical contacts 1652 are attachedto a pair of non-conductive arms 1657, which are anchored to a stablesurface 1660. A pair of springs 1655 or other such means applies forceto the non-conductive arms 1657 and thereby maintains the electricalcontacts 1652 in contact in normal operation.

Similar to the FIG. 14 embodiment, the electrical path formed across theelectrical contacts 1652 may be broken by application of a controlsignal to the deformable member 1601. To this end, a heating element1645 (such as a resistive coil) is coupled to the deformable member 1601(e.g., wrapped around the deformable member 1601, where embodied as aresistive coil). The heating element 1645 is preferably controlled by aswitch control circuit 1640 connected thereto by a pair of signal lines1641, 1642. When the switch control signal output from the switchcontrol circuit 1640 is not asserted, the heating element 1645 iseffectively disconnected (and thus inactive), and power is deliveredthrough the incoming power wire 1625 across the electrical contacts 1652to the electrical conductor 1620, from which it can be furtherdistributed to the load. When, however, the switch control signal fromthe switch control circuit 1640 is asserted, the heating element 1645heats up due to the effect of the current flowing through the heatingelement 1645, and as a result the deformable member 1601 starts to bend.Eventually, as a result of this bending, the wedge 1651 if forcedbetween the electrical contacts 1652, causing the contacts 1652 togradually separate (with springs 1655 gradually compressing), andbreaking the electrical circuit path between the incoming power signalline 1625 and the electrical conductor 1620, similar to the illustrationin FIG. 15.

Unlike the embodiment of FIG. 14, the wedge-shaped member 1651 of thecontrollable electronic switch 1600 of FIG. 16 acts as a mechanical camwith multiple latching positions, thus alleviating the need to maintainthe control signal to keep the circuit open. When the wedge-shapedmember 1651 is latched in a first position, it is removed from theelectrical contacts 1652, which remain closed, and the power signalcircuit path is uninterrupted. On the other hand, when the wedge-shapedmember 1651 is latched in a second position, it forces the electricalcontacts 1652 apart, thus interrupting the power signal circuit path. Ineither latched position, no power is required to keep the controllableelectronic switch 1600 in its current state (open or closed). Latchingof the wedge-shaped member 1651 in the various positions isaccomplished, in this example, by way of a latching member 1680comprising, e.g., an arm 1682 terminated in a ball 1681 that restsagainst the wedge-shaped member 1651. In the instant example, the arm1682 of the latching member 1680 is anchored to surface 1660, but thelatching member 1680 may be anchored to any other available surfaceinstead. Thus, in this example, the latching member 1680 is adjacent tothe arms 1657 supporting the electrical contacts 1652.

FIGS. 17-1, 17-2 and 17-3 are diagrams of different views illustratingan example of the wedge-shaped member 1651 of the controllableelectronic switch 1600 of FIG. 16, and in particular FIGS. 17-2 and 17-3illustrate the wedge-shaped member 1651 of FIG. 17-1 latched in thefirst position. The wedge-shaped member 1651 in this example comprises afront wedge section 1705 (which may be generally broad-surfaced andsloping), a central socket 1701, and a rear wedge section 1706 (whichmay be tapered and sloping) defining a shallow rear socket 1708. As bestillustrated in FIGS. 17-2 and 17-3, the ball 1681 of the latching member1680 rests on the front wedge section 1705 when the wedge-shaped member1651 is latched in the first position (the arm 1682 is omitted fromFIGS. 17-2 and 17-3 for clarifying the other features shown). The ball1681 may effectively hold the wedge-shaped member 1651 in place whenlatched in the first position, although in certain embodiments the ball1681 may not need to contact the wedge-shaped member 1651 and wouldgenerally lie in proximity therewith.

FIGS. 18-1 through 18-8 are diagrams illustrating how the wedge-shapedmember 1651 transitions between different latching positions. FIGS. 18-1and 18-2 are similar to FIGS. 17-2 and 17-3, respectively, and show thewedge-shaped member 1651 at rest in the first latched position. FIG.18-3 illustrates what happens as the deformable member 1601 is heated inresponse to the control signal being applied to the heating element 1645(shown in FIG. 16). In this situation, the deformable member 1601 startsto bend, forcing the wedge-shaped member 1651 forward. When that occurs,the ball 1681 slides over the sloping surface of the front wedge section1705, and comes to rest in the central socket 1701 of the wedge-shapedmember 1651, causing the wedge-shaped member to stabilize in the secondlatched position. For comparative purposes, the first latched positionis represented by a dotted outline 1651′ of the wedge-shaped member,although the actual dimensions of movement may be somewhat exaggeratedfor illustration purposes. In practice, movement of the wedge-shapedmember 1651 by only a few hundredths of an inch may be sufficient tochange latched positions. Even after the control signal is de-asserted,the ball 1681 retains the wedge-shaped member 1651 in the second latchedposition, by virtue of its resting firmly in the central socket 1701.The wedge-shaped member 1651 thereby keeps the contacts 1652 separatedwhile it is held in the second latching position.

Application of a subsequent control signal causes the wedge-shapedmember 1651 to return to the first latched position. When the subsequentcontrol signal is applied, the deformable member 1601 again heats up,causing it to bend and the wedge-shaped member 1651 to gravitateforwards. The ball 1681 is thereby forced out of the central socket 1701and onto the second wedge section 1706, as illustrated in FIG. 18-5. Theball 1681 slides down the tapered surface of the second wedge section1706, and due to the very narrow tail end of the second wedge section1706 (which is preferably asymmetrically tapered) the ball 1681 slidesoff the more sharply tapered side of the second sedge section 1706 andis captured by the upper lip of the shallow rear socket 1708, asillustrated in FIG. 18-6. The upper lip of the shallow rear socket 1708helps guide the ball 1681 along the outer side surface 1710 of thewedge-shaped member 1651, as illustrated from a side view in FIG. 18-7and a top view in FIG. 18-8, during which time the arm 1682 of thelatching member 1680 may be forced slightly to the side of thewedge-shaped member 1651 (or vice versa). As the deformable member 1601cools, the ball 1681 slides along the outer side surface 1710 of thewedge-shaped member 1651 and eventually reaches the narrow tip region ofthe front wedge section 1705, whereupon the arm 1682 of the latchingmember 1680 straightens out and forces the ball 1681 onto the surface ofthe front wedge section 1705, returning the wedge-shaped member 1651 tothe first latched position as illustrated in FIGS. 18-1 and 18-2.

The above process may be repeated as desired to allow the controllableelectronic switch 1680 to open and close the electrical contacts 1652 byhaving the wedge-shaped member 1651 move between the first and secondlatched positions. The control signal that is applied to cause thewedge-shaped member 1651 to move may take the form of, e.g., an impulsesignal.

FIG. 19 is a diagram of yet another embodiment of a controllableelectronic switch 1900 using a wedge-shaped member to break electricalcontacts in a circuit path, again employing principles of a mechanicalcam with multiple latching positions. In FIG. 19, the controllableelectronic switch 1900 comprises a generally elongate deformable member1901 which, as before, is formed of two layers 1902, 1903, similar innature to, e.g., the deformable member(s) 601, 1401 described previouslywith respect to FIGS. 6 and 14, respectively. In a preferred embodiment,the deformable member 1901 comprises a bimetal arm, and the two layers1902, 1903 are metallic in nature, although more generally the twolayers 1902, 1903 may be comprised of any suitable materials havingsufficiently different thermal properties to carry out the functionsdescribed herein. The deformable member 1901 is preferably anchored atone end 1906 to a non-conductive surface 1905. At its other end, thedeformable member 1901 has a wedge-shaped member 1951 that, as will bedescribed in more detail below, functions as a mechanical cam.

As further illustrated in FIG. 19, a pivoting arm 1980 is positionedbetween the first wedge-shaped member 1951 and a pair of electricalcontacts 1952. The pair of electrical contacts 1952 reside in contactwith a pair of electrical conductors 1920, 1925, the first electricalconductor 1925 serving as an incoming power wire and the secondelectrical conductor 1920 serving as a power delivery means to a load(not shown). In normal operation, power from the first electricalconductor 1925 is conducted through the electrical contacts 1952 to thesecond electrical conductor 1920 and thereby to the load. The electricalcontacts 1952 are attached to a pair of non-conductive arms 1957, whichare anchored to a stable surface (not shown). A pair of springs (notshown, but similar to springs 1655 in FIG. 16) or other such meansapplies force to the non-conductive arms 1957 and thereby maintains theelectrical contacts 1952 in contact in normal operation.

As further illustrated in FIG. 19, the pivoting arm 1980 has a ball 1981at one end and a second wedge-shaped member 1961 at the opposite end.The pivoting arm 1980 may be secured to a fixed structure 1985 at, e.g.,a generally centrally located pivoting point 1984.

The electrical path formed across the electrical contacts 1952 may bebroken by application of a control signal to the deformable member 1901.To this end, a heating element 1945 (such as a resistive coil) iscoupled to the deformable member 1901. The heating element 1945 ispreferably controlled by a switch control circuit 1940 connected theretoby a pair of signal lines 1941, 1942. When the switch control signaloutput from the switch control circuit 1940 is not asserted, the heatingelement 1945 is effectively disconnected (and thus inactive), and poweris delivered through the incoming power wire 1925 across the electricalcontacts 1952 to the electrical conductor 1920, from which it can befurther distributed to the load. When, however, the switch controlsignal from the switch control circuit 1940 is asserted, the heatingelement 1945 heats up due to the effect of the current flowing throughthe heating element 1945, and as a result the deformable member 1901starts to bend. Eventually, as a result of this bending, thewedge-shaped member 1951 presses the ball 1981 of pivoting arm 1980 suchthat it becomes displaced as the pivoting arm 1680 is forced to rotateslightly in the clockwise direction. This motion forces the other end ofthe pivoting arm 1980 to move in a clockwise direction, which in turnforces the second wedge-shaped member 1961 between the electricalcontacts 1952. This action causes the contacts 1952 to graduallyseparate, and breaks the electrical circuit path between the incomingpower signal line 1925 and the electrical conductor 1920, as illustratedin FIG. 20.

Similar the embodiment of FIG. 16, the wedge-shaped member 1951 of thecontrollable electronic switch 1900 of FIG. 19 acts as a mechanical camwith multiple latching positions, thus alleviating the need to maintainthe control signal to keep the circuit open. When the first wedge-shapedmember 1951 is latched in a first position, it causes the secondwedge-shaped member 1961 to be removed from the electrical contacts1952, which remain closed, and the power signal circuit path isuninterrupted. On the other hand, when the first wedge-shaped member1951 is latched in a second position, it causes the second wedge-shapedmember 1961 to force the electrical contacts 1952 apart, thusinterrupting the power signal circuit path. In either latched position,no power is required to keep the controllable electronic switch 1900 inits current state (open or closed). Latching of the wedge-shaped member1951 in the various positions is accomplished, in this example, by thepivoting arm 1980 which, similar to latching member 1680, is terminatedin a ball 1981 that rests against the wedge-shaped member 1951.

Motion of the ball 1981 with respect to the first wedge-shaped member1951 is similar to the described with respect to the controllableelectronic switch 1600 of FIG. 16 and the illustrations in FIGS. 17-1through 17-3 and 18-1 through 18-8. However, rather than the firstwedge-shaped member 1951 itself being inserted between the contracts1952 to open them, the first wedge-shaped member 1951 causes thepivoting arm 1980 to swing back and forth, thereby causing the secondwedge-shaped member 1961 to move forwards and backwards and to open andclose the electrical contacts 1952.

It should be noted that the embodiments illustrated in FIGS. 16 and 19,and elsewhere, are merely examples and are not intended to be exhaustivenor limiting of the concepts and principles disclosed herein. Whilecertain cam mechanisms have been described and illustrated, and cam orother similar mechanism may also be used to perform similar functions.Alternative embodiments may include, for example, any member that isused in connection with separating electrical contacts (or other type ofcircuit connection), has at least one stable position and one or moreunstable positions, and transitions between the stable and unstablepositions through application of a control signal. A variety ofdifferent mechanical structures can be utilized in place of thewedge-shaped member(s) described herein and illustrated in the drawings

FIGS. 21, 22, and 23 are simplified schematic diagrams of examples ofcontrol circuits or portions thereof that may be used with variouscontrollable electronic switches disclosed herein. In FIG. 21, a controlsignal generator 2100 includes a power source 2170 (e.g., battery orother DC source) connected via a first switch 2171 to a capacitor 2174.The capacitor 2174 is connected via a second switch 2172 to a heatingelement 2145, such as a resistive coil, which is proximate to adeformable member 2101. The heating element 2145 and deformable member2101 may represent similar components which are illustrated in FIG. 16or 19 or any of the other controllable electronic switch embodimentsdescribed herein.

In operation, the power source 2170 maintains capacitor 2174 in acharged state when switch 2171 is closed and switch 2172 is open. Sinceswitch 2172 is open, the heating element 2145 is disengaged, and thedeformable member 2101 remains in its natural unheated state. To apply acontrol signal to the heating element 2145, a control circuit (notshown) opens switch 2171 and closes 2172, as illustrated in FIG. 22. Asa result, power source 2170 is disengaged from capacitor 2174, and thecapacitor 2174 discharges into the heating element 2145. The capacitor2174 may be selected to be of sufficient size and rating to hold theappropriate amount of charge to cause heating element 2145 to heat upsufficiently to cause the deformable member 2101, particularly ifembodied as a latching cam mechanism (such as in FIGS. 16 and 19, forexample), to be forced into the next latched state. Once the capacitor2174 has been substantially discharged, switch 2171 may be closed andswitch 2172 opened, to recharge the capacitor 2174. The switches 2171,2172 may then again be toggled to discharge the capacitor 2174 a secondtime and cause the deformable member 2101, where embodied as a latchingcam mechanism, to be forced into another latched state (or returned toits original latched state).

FIG. 23 applies the same principles of FIGS. 21 and 22 to a system ofcontrollable electronic switches. The control circuit system 2300 ofFIG. 23 includes a power source 2370 and capacitor 2374 similar to thecounterparts of FIGS. 21 and 22. A first switch 2371 is analogous toswitch 2171 in FIGS. 21 and 22, and is generally closed when chargingthe capacitor 2374. When it is desired to activate the controllableelectronic switches, a control circuit 2376 opens switch 2371 and closesthe switches 2372 a, 2372 b, 2372 c, . . . associated with thecontrollable electronic switches to be activated. Only selected ones ofthe switches 2372 a, 2372 b, 2372 c, . . . need be activated, accordingto the programming of the control circuit 2376. For the switches 2372 a,2372 b, 2372 c, . . . that are closed, the respective heating elements(e.g., resistive coils) 2345 a, 2345 b, 2345 c, . . . heat up, causingdeformation of the proximate deformable members and activation of thecontrollable electronic switches according to principles previouslydescribed herein.

FIG. 24 is a diagram of an embodiment of a switch control circuit 2401as may be used in connection with various controllable electronic switchembodiments shown or described herein—for example, the controllableelectronic circuits shown in FIG. 6, 8, or 14, or others. As illustratedin FIG. 24, the switch control circuit 2401 comprises an incoming ACpower signal 2405 which is coupled to a capacitor 2408, which in turn isconnected to a heating element (not shown) via an electronic orelectro-mechanical switch 2423. A manual toggle switch or button 2420 isused to activate the electronic or electro-mechanical switch 2423, whichselectively allows the incoming power signal 2405 to pass to the heatingelement 2425. The incoming AC power signal 2405 may be, e.g.,single-phase electrical power drawn from a power line, and the designillustrated in FIG. 24 thereby provides a low cost, high efficiencymechanism (with minimal current drain) for activating the controllableelectronic switch.

FIG. 25 is a diagram of another embodiment of a switch control circuit2501 as may be used in connection with various controllable electronicswitch embodiments as shown or described herein—for example, thecontrollable electronic circuits shown in FIG. 6, 8, or 14, or others.As illustrated in FIG. 25, the switch control circuit 2501 comprises anincoming AC power signal 2505 which is coupled to a capacitor 2508,which in turn is connected to a heating element (not shown) via anelectronic 2523. A receiver 2520 receives a remote command signal viaantenna 2518 and, in response thereto, opens or closes the switch 2523,which selectively allows the incoming power signal 2405 to pass to theheating element 2525. The receiver 2520 may be configured to communicateusing any wireless technique, and may, for example, be advantageouslyconfigured to receive signals transmitted using either frequency shiftkeying (FSK) or FM sideband transmission. More complicated commands maybe delivered via the receiver 2520, thereby allowing the switch controlcircuit 2501 to be utilized as part of a circuit control system thatcontrols the states numerous controllable electronic switches and allowsmore complex processes and decisions to be carried out. The incoming ACpower signal 2505 may be, e.g., single-phase electrical power drawn froma power line, and the design illustrated in FIG. 25 thereby provides arelatively low cost, flexible, and high efficiency mechanism (withminimal current drain) for activating the controllable electronicswitch.

FIGS. 26, 28 and 30 are diagrams illustrating additional controllableswitch embodiments. FIG. 26 is a diagram of another embodiment of acontrollable electronic switch similar to the controllable switch shownin FIG. 6, but with a different location of the incoming power wireillustrated. As shown in FIG. 26, a controllable electronic switch 2600comprises a deformable member 2601, similar to FIG. 6, which may beformed in the general shape of an arm and may be comprised of two layers2602, 2603 having different thermal properties. The deformable member2601 is preferably anchored at one end 2606 to a non-conductive surface2615. At its other end, the deformable member 2601 preferably resides incontact with an electrical conductor 2620 through contacts 2612. Anincoming power wire 2625 is connected to the deformable member 2601preferably near anchor point 2606. As with FIG. 6, the electricalconductor 2620 may be connected to a load (not shown) and, in normaloperation (that is, in the absence of assertion of a switch controlsignal, as explained below), power from the power signal line 2625 isconducted through the deformable member 2601 and the electricalconductor 2620 to the load.

The conductive substances of the different layers 2602, 2603 of thedeformable member 2601 are preferably selected to have different thermalproperties such that they heat at different rates. A heating element2645 (such as a resistive coil) is coupled (e.g., wrapped around, in thecase of a resistive coil) to the deformable member 2601. The heatingelement 2645 is preferably controlled by a switch control circuit 2640in a similar manner to the controllable switch 600 of FIG. 6. When theswitch control signal output from the switch control circuit 2640 is notasserted, the heating element 2645 is effectively disconnected (and thusinactive), and power is delivered through the incoming power wire 2625over the deformable member 2601 to the electrical conductor 2620, fromwhich it can be further distributed to the load. This operation isillustrated in FIG. 27-1. On the other hand, when the switch controlsignal from the switch control circuit 2640 is asserted, the heatingelement 2645 heats up, causing the deformable member 2601 to bend andbreak the electrical circuit path between the incoming power signal line2625 and the electrical conductor 2620, as illustrated in FIG. 27-2.

So long as the switch control signal from the switch control circuit2640 is asserted, the heating element 2645 continues to keep thedeformable member 2601 bent and the electrical path between the incomingpower wire 2625 and the electrical conductor 2620 disconnected. Once theswitch control signal from the switch control circuit 2640 isde-asserted, the deformable member 2601 gradually cools, untileventually the deformable member 2601 is no longer deformed. As thisoccurs, the contacts 2612 once again form an electrical connection,allowing the power signal to pass from the incoming power wire 2625 tothe electrical conductor 2620 and then to the load.

When too much current is being drawn by the load such that anover-current situation exists, then the deformable member 2601 also willbend, breaking the electrical connectivity between the incoming powerwire 2625 and the electrical conductor 2620 (hence disconnecting powerfrom the load). Thus, the controllable electronic switch 2600illustrated in FIG. 26 may act as both a circuit breaker, responsive toover-current, and a controllable electronic switch, responsive to acontrol signal.

FIG. 28 is a diagram of a controllable electronic switch 2801, utilizinga pair of opposing deformable members (e.g., bimetal arms). As shown inFIG. 28, the controllable electronic switch 2801 includes a firstdeformable member 2851 and a second deformable member 2852, each ofwhich may be formed in the general shape of an arm, facing one another,and may, as previously described, be comprised of two layers havingdifferent thermal properties. The opposing deformable members 2851, 2852are preferably anchored to a non-conductive surface 2815. At their otherends, the deformable members 2851, 2852, when at rest, preferably residein contact with one another through contacts 2812 and 2813,respectively, and may also are separated from one another by a restingbar 2819. One of the deformable members 2852 is electrically coupled toan incoming power wire 2825, preferably near the anchor point on thenon-conductive surface 2825. The other deformable member 2851 ispreferably electrically coupled to an electrical conductor 2820 whichmay in turn be connected to a load (not shown). In normal operation(that is, in the absence of assertion of a switch control signal, asexplained below), power from the incoming power line 2825 is conductedthrough the deformable member 2852 and the electrical conductor 2820 tothe load.

The conductive substances of the different layers of the deformablemembers 2851, 2852 are preferably selected to have different thermalproperties such that they heat at different rates. When too much currentis being drawn by the load such that an over-current situation exists,then the deformable member 2652 will bend and break the connectionbetween the electrical contacts 2812, 2813, as illustrated in FIG. 29-1,thereby breaking the supply of power from the incoming power wire 2825and the electrical conductor 2820 (i.e., the load). The resting bar 2809prevents the non-circuit-breaker deformable member 2851 from followingthe bending deformable member 2852, which would otherwise hinder orprevent the bending deformable member 2852 from breaking the circuitconnection.

A heating element 2845 (in this example, resistive tape, but could alsobe a resistive coil or other means) is placed proximate to (e.g., as anadherent, in the case of a resistive tape) to one of the deformablemembers 2851. The heating element 2845 is preferably controlled by aswitch control circuit 2840 in a similar manner to the controllableswitch 600 of FIG. 6. When the switch control signal output from theswitch control circuit 2840 is not asserted, the heating element 2845 iseffectively disconnected (and thus inactive), and power is deliveredthrough the incoming power wire 2825 over the deformable member 2852 andcontacts 2812, 2813 to the electrical conductor 2820, from which it canbe further distributed to the load. This operation is conceptuallyillustrated in FIG. 28. On the other hand, when the switch controlsignal from the switch control circuit 2840 is asserted, the heatingelement 2845 heats up, causing the deformable member 2851 to bend andbreak the electrical circuit path between the incoming power signal line2825 and the electrical conductor 2820, as illustrated in FIG. 29-2. Asbefore, the resting bar 2809 prevents the non-bending deformable member2852 from following the bending deformable member 2851, which wouldotherwise hinder or prevent the bending deformable member 2851 frombreaking the circuit connection.

So long as the switch control signal from the switch control circuit2840 is asserted, the heating element 2845 continues to keep thedeformable member 2851 bent and the electrical path between the incomingpower wire 2825 and the electrical conductor 2820 decoupled. Once theswitch control signal from the switch control circuit 2840 isde-asserted, the deformable member 2851 gradually cools, untileventually the deformable member 2851 is no longer deformed. As thisoccurs, the contacts 2812, 2813 once again form an electricalconnection, allowing the power signal to pass from the incoming powerwire 2825 to the electrical conductor 2820 and then to the load.

In one aspect, the controllable electronic switch 2801 illustrated inFIG. 28 may act as both a circuit breaker, responsive to over-current,and a controllable electronic switch, responsive to a control signal.The first deformable member 2852 acts in one respect as a “safety arm,”bending in response to over-current, while the other deformable member2851 acts in one respect as a “control arm,” bending in response to acontrol signal from switch control circuit 2840.

FIG. 30 is a diagram of another embodiment of a controllable electronicswitch having opposing deformable members and a override control. Thecontrollable electronic switch 3001 in FIG. 30 is similar to that shownin FIG. 28, with elements numbered “30xx” in FIG. 30 similar to theircounterparts numbers “28xx” in FIG. 28, except that a rotatable cam 3019is used in FIG. 30 in place of a resting bar 2809 shown in FIG. 28. Thegeneral operation of the controllable electronic switch 3001 in FIG. 30is the same a that of FIG. 28. However, the rotatable cam 3019 providesa mechanism for overriding the operation of either of the deformablemembers 3051, 3052. The operation of the rotatable cam 3019 isillustrated in FIGS. 31-1 and 31-2. In FIG. 31-1 is illustrated anover-current condition that has caused deformable member 3052 to bend,breaking the circuit connection with the load. This is similar to thesituation illustrated previously in FIG. 29-1. However, rotation of therotatable cam 3019 allows the other deformable member 3051 to movetowards the opposing deformable member 3052, using the naturalspring-like tension of the deformable member 3051, until the contacts3012, 3013 eventually touch and re-connect the circuit.

A control circuit (not shown) controls the rotation of rotatable cam3019, and may be electrical or mechanical in nature. For example, thecontrol circuit may be responsive to a remote signal, or else to amanually activated electrical or mechanical switch. The amount ofrotation needed for rotatable cam 3019 to allow the deformable members3051, 3052 to contact each other may be preset. Alternatively, or inaddition, a sensing circuit along the path of electrical flow can beused to detect whether current is flowing across contacts 3012, 3013,and the control circuit can continue to rotate the rotatable cam 3019(to a limit point, if desired) until resumption of power flow isdetected by the sensing circuit.

In the exemplary embodiment shown in FIG. 30, the rotatable cam 3019provides override capability in either direction. Thus, when deformablemember 3051 is caused to bend by application of a control signal fromswitch control circuit 3040, thus stopping the flow of power to theload, the control signal may effectively be overridden by rotation ofthe rotatable cam 3019 in the opposite direction than that shown in FIG.31-2. This causes deformable member 3052 to move towards the opposingdeformable member 3051, using the natural spring-like tension of thedeformable member 3052, until the contacts 3012, 3013 eventually touchand re-connect the circuit. In other words, the override feature worksin the same way as illustrated for FIG. 31-2, but in the oppositedirection. When rotatable cam 3019 is stationary in its “normal”operating position, as illustrated in FIG. 30, it acts as a resting arm(similar to 2809 in FIG. 28), preventing the deformable members 3051,3052 from following one another when either is activated under theconditions causing them to bend and break the flow of power to the load.

An override capability such as provided by rotatable cam 3019 may beuseful in a variety of applications. For example, it may be desirable tooverride the operation of deformable member 3051 or 3052 in case of amalfunction. If the controllable electronic switch 2801 or 3001 isdeployed as part of a system for a remote control of power distributionto local loads, then it may be desirable to allow a local user tooverride a command from a remote source which has instructed deformablemember 3051 to cut off power to its load—for example, in case there isan emergency requiring the local load to receive power. Likewise, ifdeformable member 3052 has “tripped” causing a cut-off of power flow tothe local load, then an override capability may be desirableparticularly in an emergency situation where it is expected that theload can absorb the extra current. As an example, if the load is alanding gear of an airplane which has stuck, causing an overcurrentsituation and thus deformable member 3052 to trip, it may be desirableto allow a manual override capability whereby power to the landing gearcan be re-connected, especially if it is expected that the additionalpower will not harm the landing gear and/or may cause it to unjam. It isexpected that many other such situations could be envisioned by thoseskilled in the art.

While the rotatable cam 3019 is illustrated in FIG. 30 as generallysemi-circular in shape, the shape of the cam can be of any (e.g., oval)that is suitable to cause deformable members 3051, 3052 to move closerto one another when the rotatable cam 3019 is rotated. Alternatively,other types of mechanisms may be used. For example, resting bar 2809 inFIG. 28 may be slidable towards each of the deformable members 2851,2852, and can be moved towards the bending deformable member 2851 (or2852) to allow the electrical contacts 2812, 2813 to re-connect, thusproviding a similar override feature. Similarly, a tapered or conicalresting bar 2809 may be used, which can be raised and lowered, therebyincreasing and decreasing the distance between the deformable members2851, 2852 as desired. Alternatively, a bypass conductive bridge (notshown) may be moved from a normally non-contacting position to a contactposition across deformable members 2851, 2852, thus providing aneffective override by establishing an alternative path for current toflow across deformable members 2851, 2852. In short, any means may beused which results in deformable members 2851, 2852 (or 3051, 3052)rejoining their connection to allow power to flow through to the load.

In one aspect, as with the controllable electronic switch of FIG. 28,the controllable electronic switch 3001 illustrated in FIG. 30 may actas both a circuit breaker, responsive to over-current, and acontrollable electronic switch, responsive to a control signal. Thefirst deformable member 3052 acts in one respect as a “safety arm,”bending in response to over-current, while the other deformable member3051 acts in one respect as a “control arm,” bending in response to acontrol signal from switch control circuit 3040. Preferably, an overridefeature is provided whereby the operation of the control arm or safetyarm in breaking the circuit can be overridden. In the particular exampleof FIG. 30, in one aspect, a 3-position rotating cam 3019 providesoverride control, with one position being used for “normal” operatingmode, a second position for override of bending of the “safety arm,” anda third position for override of bending of the “control arm.”

Various embodiments of electronic switches as described herein have theadvantages of being simple, effective, controllable, reliable andrelatively inexpensive, and are generally capable of assisting in thecontext of a power distribution or management system in order to controlthe distribution of incoming power signals (either low voltage and/orcurrent or high voltage and/or current) from a power source to a load.In various embodiments, the controllable electronic switches are highlypower efficient—for example, they need not consume any power when theswitch is closed, and may require only minimal power to open andmaintain open. Various controllable electronic switches as disclosedherein may be operated remotely, such as via power control commandstransmitted via a remote central station, thus providing a flexible andconvenient mechanism to control power distribution.

In some embodiments, it may be desirable for the central station 102 tocommunicate bi-directionally with the power control circuits 112 at thevarious local sites 109. For example, the central station 102 may desireto obtain relatively prompt feedback on how many and/or which powercontrol circuits 112 have responded to a power alert stage by sheddingelectrical loads 120. In such an embodiment, the wireless communicationunit 115 at the various local sites would, in addition to comprising areceiver, also comprise a transmitter, and the wireless communicationunit 103 of the central station 102 would, conversely, comprise areceiver in addition to comprising a transmitter. Messages transmittedfrom the various local sites 109 may be distinguished by any of thetechniques described herein or any conventional techniques. For example,such transmissions may be distinguished by any combination of differentaddresses, frequencies, codes, and so on.

In some embodiments, the power control circuits 112 may store historicalinformation regarding their response to various power alert stage levelsdeclared via the central station 102, for billing or other purposes. Inthe embodiment shown in FIG. 2, for example, the wireless energy controlunit 214 may store such historical information in a non-volatile portionof memory 239. The historical information may include such informationas which controllable switches 262 were disengaged in response to thedeclaration of a particular power alert stage level, and/or how muchenergy consumption was reduced immediately before and after as a resultof shedding the electrical load(s) connected to the disengagedcontrollable switch(es). This type of information may be used by thepower utility in connection with providing customer incentives forreducing power consumption using a wireless energy control unit such asdescribed herein. The historical information may be transmitted uponrequest from the local power control circuits 112 to the central stationor power utility 105, assuming bi-directional communication capabilityexists in the power management system 100. Alternatively, the historicalinformation may be read out through a direct connection, or bytransmitting the information over the power lines, or by somealternative technique.

In the various embodiments disclosed herein, any appropriate means forheating the deformable member (e.g., bimetal arm) may be utilized,including not only a resistive coil, resistive tape, or a small thermalresistor, but also other means as well.

While certain embodiments have been described in the text herein and/orillustrated in the drawings, it will be understood that a variety ofchanges, modifications, additions, or substitutions may be made whichtake advantage of the principles and concepts underlying the variousembodiments described and illustrated. As but a few examples, theembodiments described herein and illustrated in the drawings may not belimited to a particular wireless technique or protocol, or a particulartype of message or power command format or sequence, or a particularcircuit configuration. Not all of the local electrical loads need to besubject to being shed by the local energy control circuits describedherein, nor is there any limitation on the types of additionalelectrical components (circuit breakers, fuses, transformers, inductors,capacitors, filters, etc.) that can be used in combination or connectionwith the various embodiments of the invention. Further, rather thanusing controllable switches which disengage and re-engage electricalloads, various embodiments may use electrical elements capable ofregulating power flow on a variable basis; however, such electricalelements generally would be expected to be more expensive and more powerconsumptive than the preferred controllable switches disclosed herein,and may require more sophisticated control, although such capabilitiesare considered within the purview of one skilled in the art given thedisclosure herein.

While preferred embodiments of the invention have been described herein,many variations are possible which remain within the concept and scopeof the invention. Such variations would become clear to one of ordinaryskill in the art after inspection of the specification and the drawings.The invention therefore is not to be restricted except within the spiritand scope of any appended claims.

1. A wireless energy control unit, comprising: a housing; a plurality ofcontrollable switches located within said housing, each of saidcontrollable switches having a first position wherein a power source iselectronically connected to an electrical load and a second positionwherein the power source is disconnected from the electrical load; aplurality of output terminals from said housing, said plurality ofoutput terminals each adapted for connection to one of a plurality ofpassive circuit breakers located in a circuit breaker panel such thatthe passive circuit breaker is connected in series with one of saidcontrollable switches, whereby the controllable switch is capable ofconnecting or disconnecting an electrical load drawing power through thepassive circuit breaker; a wireless receiver located within saidhousing; and a controller located within said housing and connected tosaid wireless receiver, said controller receiving messages via saidwireless receiver and, in response thereto, selectively switching one ormore of said controllable switches between said first position and saidsecond position according to a locally configurable priority, therebyconnecting and disconnecting the electrical loads from the power source.2. The wireless energy control unit of claim 1, further comprising asecond housing containing said circuit breakers and having disposedthereon a plurality of manual switches for resetting said circuitbreakers, wherein the first housing is integrated with or mounted on thesecond housing whereby each of said controllable switches iselectrically disposed between said power source and the electrical loadconnected to the passive circuit breaker in series with the controllableswitch.
 3. The wireless energy control unit of claim 2, furthercomprising visible status lights for each controllable switch indicatingthe on/off status of each controllable switch.
 4. The wireless energycontrol unit of claim 1, wherein an external power line is coupled tosaid housing, said wireless energy control unit further comprising adecoupling element interposed between said external power line and apower supply for the wireless energy control unit through which thewireless energy control unit draws power.
 5. The wireless energy controlunit of claim 4, wherein said decoupling element comprises a capacitor.6. The wireless energy control unit of claim 1, further comprising auser interface for configuring the controllable switches.
 7. Thewireless energy control unit of claim 6, wherein the locallyconfigurable priority is configurable via the user interface.
 8. Thewireless energy control unit of claim 1, further comprising a gas lineshutoff control output signal operated by said controller.
 9. A methodof controlling power distribution from a power source to a plurality ofelectrical loads, the method comprising the steps of: disposing, in acommon housing, a plurality of controllable switches, a wirelessreceiver, and a controller, said common housing having a user interfacefor receiving manual user commands and displaying status or otherinformation; disposing said common housing in a circuit breaker panel,and electrically connecting each of said controllable switches to apassive circuit breaker in said circuit breaker panel, whereby saidcontrollable switches are electrically disposed between a power sourceand an electrical load connected to the passive circuit breaker inseries therewith; programming a locally configurable priority via saiduser interface; receiving messages via said wireless receiver, saidmessages broadcast by a power utility; and in response to said messages,selectively switching one or more of said plurality of controllableswitches according to said locally configurable priority, therebyselectively disengaging the power source from the electrical loads inaccordance with said locally configurable priority.
 10. The method ofclaim 9, further comprising locating said circuit breakers in a secondhousing, said second housing having disposed thereon a plurality ofmanual switches for resetting said circuit breakers, wherein the firsthousing is integrated with or mounted on the second housing whereby eachof said controllable switches is electrically disposed between saidpower source and the electrical load connected to the passive circuitbreaker in series with the controllable switch.
 11. The method of claim10, further comprising activating visible status lights for eachcontrollable switch indicating the on/off status of each controllableswitch.
 12. The method of claim 9, further comprising coupling anexternal power line to said housing, said wireless energy control unitfurther comprising a decoupling element interposed between said externalpower line and a power supply for the wireless energy control unitthrough which the wireless energy control unit draws power.
 13. Themethod of claim 9, further comprising operating a gas line shutoffcontrol output signal via said controller.
 14. A wireless energy controlunit, comprising: a housing; a plurality of controllable switcheslocated within said housing, each of said controllable switches having afirst position wherein a power source is electronically connected to anelectrical load in the absence of an applied control signal and a secondposition wherein the power source is disconnected from the electricalload when the switch's control signal is applied; a plurality of outputterminals from said housing, said plurality of output terminals eachadapted for connection to one of a plurality of local electrical loads,whereby the controllable switch is capable of connecting ordisconnecting its respective electrical load; a wireless receiverlocated within said housing; an antenna coupled to said wirelessreceiver; a user interface integrated with or mounted on said housing,whereby operation of said controllable switches is selectable accordingto a locally configurable priority; and a controller located within saidhousing and electrically coupled to said wireless receiver and said userinterface, said controller receiving power utility messages via saidwireless receiver and, in response thereto, selectively switching one ormore of said controllable switches between said first position and saidsecond position according to the locally configurable priority, therebyconnecting and disconnecting the electrical loads from the power source.15. The wireless energy control unit of claim 14, further comprising asecond housing containing a plurality of circuit breakers and havingdisposed thereon a plurality of manual switches for resetting saidcircuit breakers, wherein the first housing is integrated with ormounted on the second housing whereby each of said controllable switchesis electrically disposed in series with one of the passive circuitbreakers and the switch's respective electrical load connected to thepassive circuit breaker.
 16. The wireless energy control unit of claim14, further comprising a gas line shutoff control output signal operatedby said controller.